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As a category of polymeric materials, soft dielectrics, such as most elastomers and rubber-like materials, have shown great potential for extensive applications in various fields. Owing to their intriguing electromechanical coupling behaviors, the morphological instabilities in soft dielectrics have been an active research field in recent years. In this work, the recent progress in experimental and theoretical research on their electromechanical morphological instabilities is reviewed, especially regarding the theoretical aspect. First, we revisit the theoretical framework for the electroelasticity of soft dielectrics. Then, the typical configurations of soft dielectric membranes used to generate two typical types of surface instabilities, namely wrinkles and creases, are introduced. Three commonly used modeling approaches (i.e., the stress balance method, the incremental method, and the energy method) for surface instabilities are reviewed with specific examples. Moreover, discussions on the difference between these methods and the corresponding critical loading conditions are presented. Furthermore, this review also covers the relation and transition between wrinkling and creasing phenomena. [ABSTRACT FROM AUTHOR]

In recent years, there have been many studies focused on improving the performance of active materials; however, applying these materials to active machines still presents significant challenges. In this study, we introduce a light-powered self-translation system for an asymmetric friction slider using a liquid crystal elastomer (LCE) string oscillator. The self-translation system was composed of a hollow slide, two LCE fibers, and a mass ball. Through the evolution of photothermal-induced contraction, we derived the governing equations for the system. Numerical simulations revealed two distinct motion modes: the static mode and the self-translation mode. As the mass ball moved, the LCE fibers alternated between illuminated and non-illuminated states, allowing them to effectively harvest light energy to compensate for the energy dissipation within the system. Unlike traditional self-oscillating systems that oscillate around a fixed position, the asymmetric friction enabled the slider to advance continuously through the oscillator's symmetric self-sustained oscillation. Furthermore, we explored the critical conditions necessary for initiating self-translation as well as key system parameters that influence the frequency and amplitude of the oscillator and average speed of the slider. This self-translation system, with its simple design and ease of control, holds promising potential for applications in various fields including soft robotics, energy harvesting, and active machinery. [ABSTRACT FROM AUTHOR]

This work introduces an ultraviolet (UV)-curable elastomer through the co-polymerization of aliphatic polyurethane acrylate and hydroxypropyl acrylate via UV irradiation. The UV-curable elastomer presents superior mechanical properties (elongation at a break of 2992%) and high transparency (94.8% at 550 nm in the visible light region). A robust hydrogel–elastomer stretchable sensor is fabricated by coating an ionic hydrogel on the surface of an elastomer, which enables real-time monitoring of human motion. In addition, the UV-curable elastomer can be used for 3D printing, as demonstrated by complex lattice structures using a digital light processing 3D printer. [ABSTRACT FROM AUTHOR]

In biomedical sciences, there is a demand for electronic skins with highly sensitive tactile sensors that have applications in patient monitoring, human–machine interfaces, and on‐body sensors. Sensor fabrication requires high‐performance conductive surfaces that are transparent, breathable, flexible, and easy to fabricate. It is also preferable if the electrodes are easily processable as wastes, for example, are degradable. In this work, the design and fabrication of hydrophilic silanol/amine‐terminated poly(caprolactone‐urethane) (SA‐PCLU) elastomer‐based breathable, stretchable, and biodegradable electrodes are reported. Ag nanowires dispersed in water are sprayed onto the intrinsically hydrophilic electrospun SA‐PCLU that became embedded into the scaffold and formed conformal hydrophilic polyurethane‐based conductive networks (HPCN). The electrodes are used to fabricate capacitive, curvature, and strain sensors, all having monomaterial composition. In addition to displaying particularly good transparencies at low sheet resistances, stretchability, hydrophilicity, and tight and conformal bonding with the target surface, the electrodes also allow the evaporation of perspiration, making them suitable for epidermal sensors for long‐time use. The application of the HPCN electrodes in flexible electronics and bionic skin applications is demonstrated through gesture monitoring experiments and swelling sensors. [ABSTRACT FROM AUTHOR]

Herein, a novel material design strategy is proposed: an interpenetrating composite composed of a woven orthogonal spiral metal skeleton and polyurethane (PU) elastomer. This interpenetrating composite combines rigidity and flexibility, exhibiting excellent elasticity and deformation recovery. The deformation behavior and mechanical properties of the composites under various loading conditions are investigated through experiments and numerical simulations. Different degrees of warping behaviors occur in composites with various structural parameters under uniaxial tension. Alternating rotations and double spiral arrangements can significantly limit the warping phenomenon, with a maximum reduction of 78%. The bending load capacity is regularly increased by increasing the wire diameter and decreasing the pitch. Increasing the number of loaded spiral wires enhances the bending load capacity of the composites. Uniaxial compression tests demonstrate that the composites have excellent load‐carrying capacity and strain recovery, with compressive strength 1.5 times that of pure PU. Cyclic compression tests further illustrate the excellent energy consumption capacity and stability of the composites. Overall, the introduction of orthogonal spiral skeletons into the composites demonstrates the potential to achieve enhanced load‐carrying capacity and large strain recovery simultaneously. [ABSTRACT FROM AUTHOR]

Soft ionic elastomers have attracted considerable research interest in mimicking the multiple functions of human skin. However, these ionic elastomers struggle to simultaneously achieve controllable ion dynamics and other essential performance, such as self‐healing ability and appropriate mechanical robustness. Herein, bioinspired by Piezo proteins and integrins in human skin, thioctic acid (TA)‐derived ionic elastomers with skin‐like piezo‐ionic dynamics are fabricated via a multi‐confined interaction network. This bionic network is constructed by introducing a diene comonomer and lithium salt filler into polysulfides (poly (TA)), generating many dynamic interactions (various hydrogen bonds and lithium bonds). These dynamic interactions can bind ions to the polysulfides and be destroyed under external pressure stimulation, achieving controllable ion pumping behavior. This unique design concept enables these ionic elastomers to selectively respond to pressure (the optimal sample exhibits 152 times signal intensity with a sensitivity of 49.53‐1.13 kPa−1), along with leak prevention, recyclability, and degradability. Besides, these interactions also serve as sacrificial bonds and self‐healing sites to synergistically enhance all aspects of performance, yielding a high modulus of 2.47 MPa and outstanding self‐healing efficiency of 98%. It is believed that this work could create a new approach for utilizing sustainable materials in next‐generation “green” flexible sensors. [ABSTRACT FROM AUTHOR]

Elastomer‐based interfaces provide rich functionalities for tactile sensing, particularly in making tiny differences in contact dynamics potentially detectable. However, the minimal motion‐induced changes in the elastomer's surface and their disappearance during time‐lapse limit the state recognition within the current scheme of motion recognition. In this work, a new scheme of real‐time motion mode recognition for subtle deformations is proposed, which uses an optical tactile sensing system to visualize and distinguish tiny variations in surface profile evolution encoded as images. Illustrating with a sphere, sliding‐induced asymmetric elastomer surface deformation is visualized as a “drag” in optical images. The convolutional neural network (CNN) algorithm is used to analyze the evolution of surface contour features during the interaction between the sphere and the elastic medium. Motion state recognition is achieved with 80% accuracy when a displacement of only 8.3% of the sphere diameter is produced. In addition, the system also offers the potential to analyze dynamic motion information through a single image, with an accuracy of 82.7% for velocity recognition. This dynamic real‐time recognition framework for soft media deformation paves the way for novel motion‐based input commands for tactile sensing and human‐computer interaction applications. [ABSTRACT FROM AUTHOR]

Inspired by biological mechanisms of impact protection, nanocellulose and linear polyurethane molecular chains are simultaneously tailored and expanded using supramolecular chemistry. This approach has led to the development of a novel impact protection strategy that leverages multilevel hydrogen bonding interactions. These abundant interactions effectively hinder the crystallization of polycaprolactone (PCL) chain segments, resulting in uniformly distributed microphase separation. This configuration achieves a significant fracture strength of 47.5 MPa, while maintaining an exceptional elongation at a break of 974.2%. The results demonstrate that supramolecular polyurethane‐cellulose nanofiber (SPU‐CNF) elastomer significantly reduces impact force and extends the impact buffer time. Crucially, the underlying mechanisms responsible for energy dissipation and impact protection in SPU‐CNF are elucidated. To validate these properties, impact protection tests at varying impact rates are conducted, underscoring the potential applications of the proposed SPU‐CNF in impact‐resistant materials. [ABSTRACT FROM AUTHOR]

Mechanical metamaterials achieve unprecedented mechanical properties through their periodically interconnected unit cell structure. However, their geometrical design and resulting mechanical properties are typically fixed during fabrication. Despite efforts to implement covalent adaptable networks (CANs) into metamaterials for permanent shape reconfigurability, emphasis is given to global rather than local shape reconfiguration. Furthermore, the change of effective material properties like Poisson's ratio remains to be explored. In this work, a non‐isocyanate polyurethane elastomeric CAN, which can be thermally reconfigured, is introduced into a metamaterial architecture. Structural reconfiguration allows for the local and global reprogramming of the Poisson's ratio with change of unit cell angle from 60° to 90° for the auxetic and 120° to 90° for the honeycomb metamaterial. The respective Poisson's ratio changes from −1.4 up to −0.4 for the auxetic and from +0.7 to +0.2 for the honeycomb metamaterial. Carbon nanotubes are deposited on the metamaterials to enable global and spatial electrothermal heating for on‐demand reshaping with a heterogeneous Poisson's ratio ranging from −2 to ≈0 for a single auxetic or +0.6 to ≈0 for a single honeycomb metamaterial. Finite element simulations reveal how permanent geometrical reconfiguration results from locally and globally relaxed heated patterns. [ABSTRACT FROM AUTHOR]

Tetrafluoroethylene (TFE) terpolymers have emerged as advantageous substitutes for polytetrafluoroethylene (PTFE). Therefore, they are being considered as alternatives to PTFE in many application areas. The advantages of TFE terpolymers include their facile processability at elevated temperatures, their solubility in some polar organic solvents, their inertness against aqueous acids, aqueous bases and a large number of mostly nonpolar organic solvents, their low dielectric constant, their low refractive index as well as useful electro‐ and thermochemical properties. This review on TFE terpolymers focuses on their processing including shaping and surface modification as well as on selected properties including wettability, dielectric properties, mechanical response behavior, chemical stability, and degradability. Applications including their use as elastomeric sealing material, liner and cladding layer as well as their use as material for membranes, microfluidic devices, photonics, photovoltaics, energy storage, energy harvesting, sensors, and nanothermitic composites will be discussed. The review concludes with a discussion of the future potential of TFE terpolymers and scientific challenges to be addressed by future research on TFE terpolymers. [ABSTRACT FROM AUTHOR]

A hybrid film that exhibits reversible fluorescence (FL) is prepared by embedding a conjugated polymer, having an intramolecular stacking structure of the side phenyl rings, in a highly dispersed state into a silicone elastomer. The hybrid film experiences significant FL quenching during stretching and restores its original FL when the external stress is removed. In particular, the hybrid film manufactured using a shadow-masked, plasma-treated silicone elastomer provides a high-resolution FL image, which disappears when the film is stretched and reappears when the external stress is removed. The hybrid film can be applied as a strain-gauge sensor or a security film with embedded images that can be mechanically erased and regenerated. [ABSTRACT FROM AUTHOR]

This study presents data on the use of shungite ore (the Bakyrchik deposit, Kazakhstan) and its concentrate as fillers in elastomer composites based on nitrile butadiene rubber. In addition to carbon, these shungite materials contain oxides of Si, Fe, K, Ca, Ti, Mn, and Al. The shungite concentrate was obtained through a flotation process involving five stages. The chemical composition analysis of these natural fillers revealed that during flotation, the carbon content increased 3.5 times (from 11.0 wt% to 39.0 wt%), while the silicon oxide content decreased threefold (from 49.4 wt% to 13.6 wt%). The contents of oxides of K, Ca, Ti, Mn, and Al decreased by less than 1%, and iron oxide content increased by 40% (from 6.7 wt% to 9.4 wt%). The study explored the impact of partial or full replacement of carbon black (CB) of P 324 grade with the shungite ore (ShO) and the shungite concentrate (ShC) on the vulcanization process and the physical–mechanical properties of the rubber. It was found that replacing CB with ShO and ShC reduces Mooney viscosity ML (1 + 4) 100 °C of the rubber compounds by up to 29% compared to the standard CB-filled sample. The use of the shungite fillers also increased scorch time (ts) by up to 36% and cure time (t90) by up to 35%. The carbon content in the shungite fillers had little influence on these parameters. Furthermore, it was demonstrated that replacing 5–10 wt% of CB with ShO or ShC improves the tensile strength of the rubber. The results of the flotation enrichment process enable the assessment of how these shungite fillers affect the properties of the composites for producing rubbers with specific characteristics. It was also found that substituting CB with ShO or ShC does not significantly affect the rubber's resistance to standard oil-based media. The findings indicate that Kazakhstan's shungite materials can be used as fillers in rubber to partially replace CB. [ABSTRACT FROM AUTHOR]

Thermally conductive composites were prepared based on epoxidized natural rubber (ENR) filled with alumina, silica, and hybrid alumina and silica. The thermal conductivity and mechanical properties were assessed. It was observed that the interactions of polar functional groups in the fillers and epoxy group in ENR supported a fine dispersion of filler in the ENR matrix. The mechanical properties were improved with alumina, silica, and hybrid alumina/silica loadings. The ENR/Silica composite at 50 phr of silica provided the highest 60 shore A hardness, a maximum 100% modulus up to 0.37 MPa, and the highest tensile strength of 27.3 MPa, while ENR/Alumina with 50 phr alumina gave the best thermal conductivity. The hybrid alumina/silica filler at 25/25 phr significantly improved the mechanical properties and thermal conductivity in an ENR composite. That is, the thermal conductivity of the ENR/Hybrid filler was 2.23 W/mK, much higher than that of gum ENR (1.16 W/mK). The experimental results were further analyzed using ANOVA and it was found that the ENR/Hybrid filler showed significant increases in mechanical and thermal properties compared to gum ENR. Moreover, silica in the hybrid composites contributed to higher strength when compared to both gum ENR and ENR/Alumina composites. The hybrid filler system also favors process ability with energy savings. As a result, ENR filled with hybrid alumina/silica is an alternative thermally conductive elastomeric material to expensive silicone rubber, and it could have commercial applications in the fabrication of electronic devices, solar energy conversion, rechargeable batteries, and sensors. [ABSTRACT FROM AUTHOR]

The work examines the influence of linear low-density polyethylene on the basic technological, physical-mechanical and fatigue properties of elastomeric materials based on synthetic isoprene rubber of the SKI-3 brand. Synthetic polyisoprene rubber of SKI-3 brand manufactured by LLC “Togliattikauchuk” was used as synthetic polyisoprene rubber, and LLDPE 218 BJ manufactured by SABIC was used as linear low-density polyethylene. Rubber blends were made in a Haake PolyLab rubber mixer for 9 minutes with further introduction of sulfur on rollers for 1.5 minutes. It was found that the introduction of linear low-density polyethylene into the rubber mixture leads to a significant increase in green strength (up to the level of natural rubber and even higher). It has also been established that LLDPE increases the Mooney viscosity of the rubber compound, the stress at 100% and 300% elongation and increases the residual elongation after rupture of the vulcanizates, but has virtually no effect on the vulcanization process of the rubber compound and has an insignificant effect on the tensile strength. The fatigue characteristics of vulcanizates containing LLDPE up to 7 wt.% are at the level of the vulcanizate based on natural rubber. It has been shown that the combination of synthetic polyisoprene brand SKI-3 with linear low-density polyethylene LLDPE 218 BJ at a component ratio of 93/7 allows obtaining an elastomeric material approaching the elastomeric material based on natural rubber RRS1 in key indicators (first of all, in terms of green strength). [ABSTRACT FROM AUTHOR]

An improved X-ray apparatus that combines tensile testing and X-ray diffraction has been designed and constructed to conduct timeresolved experiments during uniaxial stretching. By utilizing mortise-like clamping jaws and dogbone-shaped specimens, this setup allows for the simultaneous recording of high-quality mechanical responses and 2D diffraction patterns due to the minimization of experimental errors from sample slippage or premature fracture. Furthermore, the local extension ratio can be accurately determined based on thickness variation, and the Hermans' orientation function was demonstrated to be a reliable method with high accuracy to calculate the segmental orientation parameter 〈P2〉 in elastomeric samples under high degree of stretching. In summary, this innovative tensile-WAXD instrument has proven to be a promising and powerful technique for investigating the "stress-deformation-segmental orientation" relationship in elastomers with high extensibilities. [ABSTRACT FROM AUTHOR]

In particle-filled polymer composites with selective distributions of fillers in one phase, much attention has been focused on the "volume exclusion effect" in reducing the percolation threshold of filler, while the role of dispersed polymer phase acting as bridges of fillers in the particle network has largely been ignored. Herein, we studied industrially important ternary composites, polypropylene (PP)/ethylene-octene copolymer (a polyolefin elastomer, POE)/talc systems, and adopted rheology to reveal the bridging behavior of POE droplets in the network of talc particles. It is found that talc fillers concentrate in the PP phase using the "blend first" protocol, while more talc particles are located at the interface of PP and POE phases using the "filler first" protocol. Changing the POE viscosity and talc size can affect the migration of talc from the POE phase to the PP phase in the "filler first" protocol. The linear rheology behavior indicates that besides the "volume exclusion effect", the talc-POE hybrid network can further contribute to the reinforcement effect. Meanwhile, the POE droplet bridging structure can facilitate the rebuilding of the hybrid network after large amplitude oscillatory shear, in contrast to the un-recoverable structures in the PP/talc binary composites. The correlation between rheology and selective distribution of fillers in ternary composites may provide practical guidance for processing and designing advanced polymer composites with controlled selective location of fillers. [ABSTRACT FROM AUTHOR]

Masonry infills are frequently employed as both outer and inner partitions in reinforced concrete (RC) frame structures due to their outstanding characteristics in terms of energy efficiency, fire resistance and sound isolation. However, common construction practice typically involves the mortar connection between masonry infills and RC frames. For this reason, the unforeseen frame-infill interaction takes part under seismic loading, which leads to severe and uncontrollable damage to masonry infills. This interaction also causes damage or even the collapse of the RC frames and thus of the whole structures. The poor performance of infilled RC frame structures in recent earthquake events is a strong motivation for the development of innovative engineering solutions, which aim to mitigate the detrimental effects of frame-infill interaction. This article introduces an innovative decoupling system founded on the concept of decoupling the RC frame from the masonry infill. The decoupling is achieved by inserting elastomeric material between the masonry infill and RC frame. The properly designed decoupling system allows infill activation only at high in-plane drifts. Simultaneously, it provides boundary conditions for seismic loads acting perpendicular to the infill plane. Firstly, the article explains the design of the masonry infill with the decoupling system and its installation. Afterwards, the results of small specimen tests carried out to determine the load-bearing capacity of the decoupling system are presented. Furthermore, the article discusses the findings of an extensive experimental campaign conducted on nine real-size RC frames with decoupled infills subjected to separate and combined in-plane and out-of-plane loadings. In addition to different loading types, various infill configurations are considered – solid infill, infill with centric window, and infill with centric door opening. Finally, the experimental results of RC frames with decoupled infills are compared with the experimental results of traditionally infilled RC frames, which were tested within the framework of the same project. The thorough evaluation and comparison of the experimental findings demonstrate the significant improvement of seismic performance of infilled RC frames if the decoupling system is applied. [ABSTRACT FROM AUTHOR]

The absorbent expansion elastomer plays a crucial role in engineering sealing and holds a promising future in this field as infrastructure continues to develop. Traditional materials have their limitations, especially when used in large construction projects where the integrity and reliability of the material are of utmost importance. In this work, a self‐healing water‐absorbing expansion elastomer was developed for continuous production at a large scale to monitor the sealing conditions of massive infrastructure projects. At room temperature, the material exhibited a repairing efficiency of 57.77 % within 2 h, which increased to 84.02 % after 12 h. This extended reaction time allowed for effective repairs when defects were detected. The material's strength can attain 3 MPa, placing it at the upper echelon among common self‐healing materials, thereby granting it a certain level of durability in its application environment. The material's volume expansion rate reached 200–400 % to achieve effective sealing, and the functional filling of the filler endowed the material itself with a favorable external force induction effect and prevented heat accumulation. The conductive detection performance of the absorbent expansion elastomer was improved by utilizing triple self‐healing strategies, including dipole‐dipole interaction, ion cross‐linked network, and externally‐aided restoration materials. These strategies were combined with a double packing strategy to enhance the material's properties. This innovative elastomer can be applied in various fields such as tunnel construction, infrastructure development, aerospace sealing, and railway transportation, showcasing significant potential for diverse engineering applications. [ABSTRACT FROM AUTHOR]

Recently, there has been growing interest in materials that combine the advantages of glass and polymer materials. Such a combination results in a kind of hybrid glass-polymer optics that meets the requirements for high-quality imaging in various environmental conditions. So far, the literature on these materials is quite scarce. This article is an attempt to review the most important reports on the topic of available polymers with optical properties, dividing them into groups, i.e. synthetic optical polymers (including polymethylmethacrylate, polyethylene terephthalate, polypropylene, cyclic olefin copolymers and polyolefin elastomers) and biopolymers (including polylactide and gelatin). A separate place and chapter is given to transparent CR-39 plastic and the issue of individual dosimetry for radon detection. Moreover, testing methods for measuring the most important optical properties of polymers and their major applications are briefly discussed. [ABSTRACT FROM AUTHOR]

The limited utilisation of epoxy asphalt primarily stems from its inherent brittle cracking behaviour. This investigation aims to mitigate this issue by introducing styrene–butadiene-styrene/crumb rubber modified asphalt (SBS/CRMA). Furthermore, this research assesses the influence of SBS/CRMA on the curing behaviour of epoxy asphalt (EA) and the low-temperature fracture characteristics of epoxy asphalt concrete (EAC). The curing behaviour of EA was systematically examined using diverse analytical techniques, including attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR), rotational viscosity, and non-isothermal curing kinetics analysis. Notably, SBS/CRMA expedites the curing process of epoxy asphalt, possibly attributed to the amine constituents in the crumb rubber, which acts as catalyst. Subsequently, the study scrutinised the fracture characteristics of EAC through the application of the semicircle bending (SCB) test and acoustic emission (AE) methodology. The results substantiate that SBS/CRMEAC imparts a proficient toughening effect, underpinned by an augmented stress relaxation capacity due to the reinforcing influence of elastomers such as crumb rubber and SBS. The fracture process was delineated into three distinct stage and the AE signal in matrix epoxy asphalt (MEA) exhibited concentration during the macroscopic crack extension and final fracture stages. In stark contrast, SBS/CRMEAC exhibited a uniform distribution and showcased ductile fracture characteristics. [ABSTRACT FROM AUTHOR]

Hydrogels are soft materials widely used as a substrate or matrix for cell culture to mimic the physicochemical, structural, and mechanical properties of the cell's native microenvironment. Recently, a growing body of evidence has shown that substrate topography is a key determinant of cell behavior. These studies, however, mostly rely on the use of hard elastomeric materials, particularly as introducing topography in soft hydrogels is technically challenging, labor intensive, and often does not provide a flexible design space. Here, a new approach is presented that allows robust creation of topographies on hydrogels using a maskless and contactless UV‐sculpting approach. The sculpted topographies are highly programmable: the features can be designed using any digital drawing software, while the dimensions and resolution can be easily tuned via UV exposure dose or photoinitiator concentration. Microscale topographies (2–100 µm in size) can be created on a wide range of hydrogels with diverse chemical characters and mechanical properties (e.g., stiffness). As a proof of concept, this work shows that adherent cells on softer hydrogels align better to topographical cues than on stiffer hydrogels, underlining the importance of studying cell behavior in physiologically more relevant multi‐cue environments. [ABSTRACT FROM AUTHOR]

Background: The effectiveness of newly developed elastomeric polymer hybrid siloxane (PVES), which combines the properties of polyethylene (PE) and polyvinyl siloxane (PVS) elastomers, has been a subject of interest in recent studies. This study aimed to assess the physical properties of hybrid PVES materials by analyzing existing data from recent studies on this topic. Methods: A systematic literature search was conducted to retrieve peer-reviewed articles published up to February 5, 2023. The population, intervention, comparison, and pertinent outcomes were specified under the PICO framework. The primary data analysis was performed in Microsoft Excel, while statistical analysis used Meta-Essentials. Results: Of the 1152 articles assessed, 14 met the inclusion criteria. The meta-analysis of the selected studies indicated that polyether (PE) and polyvinyl siloxane (PVS) were highly correlated (two-tailed p-values of 0.000 and 0.001, respectively) with the improved tensile strength of vinyl polyether siloxane (PVES) with a significantly positive effect size. Similarly, the hydrophilic characteristics of PVES were significantly improved compared to those of PE and PVS. PE was a significant contributor to the hydrophilic characteristics of PVES, with a two-tailed p-value of 0.000. The effect size was highly positive for hydrophilicity but showed high heterogeneity. It was also observed that the dimensional accuracy of PVES was comparable to those of PE and PVS, with no statistically significant differences among the three materials. Conclusions: PVES showed promising features, with improved tensile strength and hydrophilic characteristics compared to those of PE and PVS. [ABSTRACT FROM AUTHOR]

Emulating very soft tissues with synthetic materials is important for clinical prosthetists who want to improve compliance in maxillofacial and breast prosthesis. It is equally important for theatrical prosthetists wanting to model bariatric conditions and soft organs for surgical or palpation training. Polydimethylsiloxane (PDMS) gels, which are often used in medical model construction, are stiff and highly elastic compared to the friable soft tissues found in the body. Silicone oil is known to soften PDMS gels, but it is not known precisely how oil dispersal affects these gels and what proportion of oil is needed to simulate very soft tissue membranes like adipose tissue. In this work, internationally agreed test standards were used to mechanically characterize a range of PDMS gel membranes saturated with different amounts of silicone oil to determine whether materials with behavioral similarities to adipose tissue could be created. Mechanical properties like hardness, elasticity, strength, viscoelastic behavior and cure-time are presented in this study, which are all key factors required by the creators of such membranes. Results were compared to identical tests on porcine fat and data in the literature for porcine and human fat. The data revealed a strong correlation between increases in oil content and decreases in membrane hardness, strength and elastic modulus. It was also found that increases in oil content caused proportional increases in cure time, while membranes with equal amounts of oil and gel were best at mimicking characteristics of human and porcine fat, like hardness and elasticity. [ABSTRACT FROM AUTHOR]

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Purpose: In industrial applications, couplings are widely utilised, primarily to connect prime movers to process machines. However, coupling must contend with various induced moments, additional load toque, stress under vibrations, and misalignment during operation. One of the most significant challenges it encounters is shaft misalignment. Furthermore, due to misalignment, a cyclic load generates additional moments at the bearing, escalating time-varying bearing reactions at the bearing cap. Methods: The bearing cap vibrations are caused by this time-varying reaction. The dynamics of a two-jaw elastomeric coupling are evaluated in this context for three sixty-degree rotations while in a predetermined misalignment position. Results: The analysis reveals that the load on the jaws of coupling follows a cosine cyclic curve. Findings also reveal that certain misalignment angles increase vibration amplitude, with critical thresholds that affect coupling lifespan and machinery performance. As a result, the load induced at the motor shaft appears to fluctuate. The maximum bearing cap vibrations found as 0.00014 mm. The vibration pattern of a single coupling rotation is identified as periodic. This pattern is expected to become aperiodic as the induced jaw load cyclic pattern becomes distorted due to shaft pulling during coupling rotation. A comprehensive analysis will be expounded upon in the following sections. Shaft tugging can result from extreme misalignment. Because the second shaft pulled it inline when one shaft rotated fully. Conclusions: This study helps to improve industrial machinery reliability by elucidating complex dynamics of coupling behaviour. Further research should focus on adaptive control strategies that dynamically adjust to misalignment to strengthen industrial systems against vibration-induced failures. The findings could also be applied to more industrial scenarios by analyzing different elastomeric materials. [ABSTRACT FROM AUTHOR]

Since the invention of polymer networks such as cross-linked natural rubber in the 19th century, it has been a dogma that stiffer networks are less stretchable. We report a universal strategy for decoupling the stiffness and extensibility of single-network elastomers. Instead of using linear polymers as network strands, we use foldable bottlebrush polymers, which feature a collapsed backbone grafted with many linear side chains. Upon elongation, the collapsed backbone unfolds to release stored length, enabling remarkable extensibility. By contrast, the network elastic modulus is inversely proportional to network strand mass and is determined by the side chains. We validate this concept by creating single-network elastomers with nearly constant Young's modulus (30 kilopascals) while increasing tensile breaking strain by 40-fold, from 20 to 800%. We show that this strategy applies to networks of different polymer species and topologies. Our discovery opens an avenue for developing polymeric materials with extraordinary mechanical properties. [ABSTRACT FROM AUTHOR]

Refreshable Braille display systems offer dynamic tactile approaches for the blind to obtain text information. However, existing refreshable Braille display systems using soft‐actuator‐driven Braille dots exhibit limitations of small strokes, complex mechanical structures, and high‐driving voltages, which inevitably lead to serious issues in safety, flexibility, and portability. To handle these issues, a novel refreshable Braille display system leveraging accordion‐fold liquid crystal elastomer actuators (AF‐LCEAs) is designed and created, which feature high stroke (1.47 mm), simple mechanical structure, and low driving voltage (20 V). The accordion‐fold structure with a high folding ratio of 59.7% not only enables significantly amplifying actuation strokes, but also brings a compact mechanical architecture for Braille dots. The structured‐LCE‐based refreshable Braille display system can be assembled modularly by multiple display units, which provides the capability to deliver rich and complex tactile information. In addition, a digital electro‐control matrix is designed to enable addressable, programmable electro‐actuation of the multiple LCE Braille dots to enable complicated refreshable tactile patterns. The Braille display system offers a versatile approach to engineering refreshable, portable, small‐sized Braille books useful for the blind. [ABSTRACT FROM AUTHOR]

Anisotropic volume changes in primary particles of layered Ni‐rich transition metal oxides generate mechanical stresses during electrochemical cycling. This results in structural degradation and side reactions that deteriorate battery performance. To address this issue, a cross‐linked epoxy natural rubber (CENR) is employed as the protective elastomeric interphase. The viscoelastic properties of CENR facilitated a strong adhesion to the surface of Ni‐rich cathodes, thereby helping alleviate mechanical stresses during cycling. This approach maintained the structural integrity of the Ni‐rich cathodes and suppressed detrimental interfacial reactions. Consequently, the fortified Ni‐rich cathode retained 95.9% of its capacity after 300 cycles at 0.5 C and 82.8% after 500 cycles at 1 C. This study highlights the essential role of elastomeric materials in stabilizing Ni‐rich cathodes and offers insights that can enable the development of additional protective elastomeric layers for battery electrode materials. [ABSTRACT FROM AUTHOR]

Dielectric elastomers (DEs) are widely studied and applied as an artificial muscle owing to their combined features of large actuation strain, fast response, high energy density, and low noise. However, scalable fabrication of dielectric elastomer actuators (DEAs) with low driving voltages (100 s of volts) and high mechanical outputs remains challenging, which significantly limits their wider applications. In this work, processable, high‐performance dielectric elastomer (PHDE) ultra‐thin film based multilayer DEAs (PUT‐MDEAs) through an optimized dry‐stacking process are fabricated. The obtained ten‐layer PUT‐MDEAs show actuation at 200 V and reach a maximum areal strain of ≈80% at 800 V. They deliver a blocked force of 0.1 N and an energy density of 22 J kg−1 at 200 V and achieve a blocked force of 0.7 N and an energy density of 50 J kg−1 at 700 V. In addition, large‐area PUT‐MDEAs are fabricated using the scalable dry‐stacking method, and adopted to build low‐driving‐voltage soft pumps and robotic fish, showing their potential for practical applications. [ABSTRACT FROM AUTHOR]

The key issue in utilizing solid polymer electrolytes for high‐energy‐density lithium metal batteries is to balance the conflicting demands of superior processability, adequate ionic conductivity, and mechanical stability. Inspired by molecular structure design, a metal‐organic framework‐derived polyether poly(urethane urea) solid polymer electrolyte (denoted as ePU@H SPE) has been synthesized via a facile polycondensation method involving covalent crosslinking. The reduced crystallinity and numerous polar groups in ePU@H SPEs enhance Li salt dissociation and create efficient Li+ ion diffusion channels, yielding remarkable ionic conductivity (1.48 × 10−4 S cm−1). The polymer backbones, incorporating covalent bonds and dynamic hydrogen bonds, provide superb mechanical strength (5.12 GPa), high toughness (1240%), and excellent resilience, which suppress lithium dendrite growth and buffer electrode volume fluctuations during cycling. Leveraging these attributes, the well‐designed ePU@H SPE enables ultra‐high durability in lithium plating/stripping over 2300 h. Moreover, the integrated LFP|ePU@H|Li batteries, generating delicate electrode/electrolyte interfacial contact, deliver an exceptionally long lifespan (86% retention over 500 cycles at 1 C). Moreover, the LFP|ePU@H|Li pouch cell operates reliably even under severe deformation and external damage. Impressively, the stable cycling performance of full batteries incorporating high‐voltage LCO and high‐capacity S cathodes further verifies the significant potential of advanced ePU@H SPEs for practical applications. [ABSTRACT FROM AUTHOR]

Recently, renewable bio‐based materials have received more and more attention due to environmental issues such as global warming and ecosystem destruction. In the present work, a series of isosorbide‐based bioelastomers poly(isosorbide carbonate‐co‐butanediol aliphatic esters)s (PICBAs) are synthesized by a facile and economical two‐step melt polycondensation. Due to the slightly self‐crosslinking reaction of isosorbide, PICBAs exhibit excellent tensile strength and self‐healing ability, the mechanical properties of PICBAs can recover over 95% after 48 h under room temperature. In addition, PICBAs can stick different substances, such as glass, rubber, plastic, and stones, and show better adhesive performance than 3M commercially available double‐sided tape. Consequently, isosorbide‐based bioelastomers PICBAs are of great potential to be used as environmentally friendly pressure‐sensitive adhesives (PSA) in the future. [ABSTRACT FROM AUTHOR]

Zeolites, known for their unique structural and catalytic properties, are added to the natural rubber matrix to investigate their influence on the vulcanization process and the resultant properties of composites. The natural rubber-based composites were masticated with 4A synthetic zeolite (0, 5, 10, 15, 20, and 30 phr). The curing of the rubber compounds was monitored on a moving die rheometer at 150 °C. The isothermal DSC method was also used to study the curing process at 150 °C, 160 °C, and 170 °C. Based on the obtained results, it is assumed that there is an interaction between the components of the curing system and the surface of the zeolite particle, and that is why the vulcanization reaction starts earlier with an increase in zeolite in the rubber mixture. This underscores the significant role of zeolite in accelerating the curing reaction of natural rubber-based compounds. The composites were vulcanized in a press at 150 °C for 15 min. The chemical structure was analyzed using FTIR, and the sample morphology was examined using SEM. The degree of swelling in toluene and distilled water was determined. The tensile strength values, modulus of elasticity at 100% and 300% elongation, and elongation at break were measured using a universal testing machine. Hardness was assessed according to the Shore A scale. With a small addition of zeolite (up to 10 phr), there is no significant change in the tensile strength values. However, adding a considerable amount of zeolite to a natural rubber matrix results in a deterioration of the tested mechanical properties. It can be assumed that with large proportions of zeolite 4A MS in the composites, the mechanical properties deteriorated due to increased porosity. The amount of added zeolite affects the initial stages of thermal decomposition of the examined samples and the rest after the analysis at a temperature of 500 °C. [ABSTRACT FROM AUTHOR]

Due to its ability to achieve geometric complexity at high resolution and low length scales, additive manufacturing (AM) has increasingly been used for fabricating cellular structures (e.g., foams and lattices) for a variety of applications. Specifically, elastomeric cellular structures offer tunability of compliance as well as energy absorption and dissipation characteristics. However, there are limited data available on compression properties for printed elastomeric cellular structures of different designs and testing parameters. In this work, the authors evaluate how unit cell topology, part size, the rate of compression, and aging affect the compressive response of polyurethane-based simple cubic, body-centered, and gyroid structures formed by vat photopolymerization AM. Finite element simulations incorporating hyperelastic and viscoelastic models were used to describe the data, and the simulated results compared well with the experimental data. Of the designs tested, only the parts with the body-centered unit cell exhibited differences in stress–strain responses at different part sizes. Of the compression rates tested, the highest displacement rate (1000 mm/min) often caused stiffer compressive behavior, indicating deviation from the quasi-static assumption and approaching the intermediate rate response. The cellular structures did not change in compression properties across five weeks of aging time, which is desirable for cushioning applications. This work advances knowledge on the structure–property relationships of printed elastomeric cellular materials, which will enable more predictable compressive properties that can be traced to specific unit cell designs. [ABSTRACT FROM AUTHOR]

The polymeric materials can simultaneously possess high mechanical properties and outstanding self‐healing performance under mild condition have found widespread applications in various fields. However, this type of polymers is exceedingly rare due to the trade‐off between mechanical robustness and chain flexibility for healing. In this study, we designed a facile strategy for synergistic integration of dynamic acylsemicarbazide (ASC) bonds and disulfide bonds into polyurethane elastomer by the reaction between 3,3′‐dithiobis(propionohydrazide) and isocyanate‐terminated Pre‐PU. The obtained elastomer ASC‐SS‐PU not only possesses an outstanding tensile strength (17.1 MPa), good stretchability (735%) and high toughness (57.16 MJ·m−3), but also exhibits excellent self‐healing performance under mild condition. The healing efficiency of the damaged ASC‐SS‐PU samples (breakage rate >90%) can reach over 70% healing at 60°C for 40 min, which is much lower than conventional ASC‐based PU elastomer. Considering the simple and easy‐to‐scaleup preparation process and commercially available low‐cost raw materials, outstanding mechanical strength and toughness, as well as high healing efficiency under mild condition, the ASC‐SS‐PU elastomer as self‐healing but strong materials have great potential for use in various fields. [ABSTRACT FROM AUTHOR]

Polyolefin elastomer (POE) has very weak crystalline ability, consequently, applying the conventional preparative temperature‐rising elution fractionation (P‐TREF) to separate is challenging. Here, a unique, home‐built P‐TREF apparatus with an extensive range of temperatures from −80°C to 150°C is applied to first fractionate POE depending on its crystallizability. The main fractions are eluted at 0°C, 8°C, 15°C, 20°C, 25°C, 30°C, and 35°C. The corresponding weight percentages of fractions are 8.31, 13.38, 15.59, 12.05, 13.39, 17.30, and 10.53 wt%, respectively. The chain structures of fractions are further analyzed by high‐temperature gel permeation chromatography (HT‐GPC), 13C‐nuclear magnetic resonance spectroscopy (13C‐NMR), differential scanning calorimetry (DSC), and successive self‐nucleation and annealing (SSA). The crystallinity of the fraction grows continually as the elution temperature rises. The 1‐octene comonomer concentrations within the fractions decreases from 13.8 to 7.9 mol% when the elution temperature rises from −10°C to 40°C. These findings enable for the detailed recognition of the chain microstructure of POE resin and the extension of the TREF approach to POE resins. This lays the groundwork for fundamental studies and practical uses in industry. [ABSTRACT FROM AUTHOR]

A CO2‐based thermoplastic elastomer, poly(propylene carbonate)‐multiblock‐polyamide6 (PPC‐mb‐PA6) copolymer, was constructed through coupling amorphous/soft PPC blocks with crystalline/hard PA6 blocks. The PPC‐mb‐PA6 copolymers with different block length pairs were designed and synthesized, and then fully characterized by structural, thermal, and mechanical analysis. The proton nuclear magnetic resonance (1H‐NMR), diffusion ordered spectroscopy (DOSY), heteronuclear multiple‐bond correlation (HMBC) and gel permeation chromatography (GPC) results confirm that the multiblock sequence structure of PPC‐mb‐PA6. The differential scanning calorimetry (DSC) tests show that all PPC‐mb‐PA6s possess melting points around 179–206°C. The thermal and mechanical analysis indicates improved service temperatures (T5% up to 270°C) and tensile strength ranging from 15.8 to 39.6 MPa with higher PA6 content. The dynamic mechanical analysis demonstrates excellent shape memory effect of PPC‐mb‐PA6 with thermal stimuli responsiveness derived from the micro phase separation between soft PPC and hard PA6 domains. And the characteristic strain fixity parameter (Rf) and deformation recovery rate (Rr) are 98% and 100%, respectively, which are comparable with other excellent shape memory polymers. [ABSTRACT FROM AUTHOR]

Bio‐based elastomers and composites are of great interest in numerous applications for environmental sustainability. In this study, bio‐based elastomers with low hysteresis are developed from epoxied soybean oil (ESO) with tetradecanedioic acid (TA) as the curing agent. The as‐prepared ESO/TA thermosets are in the rubbery state at room temperature, with a glass transition temperature (Tg) falling between −19°C and −27°C depending on the amount of TA. With optimized amounts of TA, the elongation at break of ESO/TA thermosets exceeds 130%. ESO/TA thermosets display a stress‐softening behavior and remarkable resilience with low residual strain (<1%) and hysteresis (<7%) after removal of irregular crosslinks and/or interactions by the first stretching. The adhesion of ESO/TA thermosets to wood is also examined through adjustments to the pressure and temperature that are applied for curing. ESO/TA thermosets are then used as the matrix to prepare wood‐polymer composites. Their flexural properties are explored to demonstrate the potential for using ESO/TA thermosets in eco‐friendly wood‐polymer composites. [ABSTRACT FROM AUTHOR]

Ion‐conductive elastomers capable of damping can significantly mitigate the interference caused by mechanical noise during data acquisition in wearable and biomedical devices. However, currently available damping elastomers often lack robust mechanical properties and have a narrow temperature range for effective damping. Here, precise modulation of weak to strong ion‐dipole interactions plays a crucial role in bolstering network stability and tuning the relaxation behavior of supramolecular ion‐conductive elastomers (SICEs). The SICEs exhibit impressive mechanical properties, including a modulus of 13.2 MPa, a toughness of 65.6 MJ m−3, and a fracture energy of 74.9 kJ m−2. Additionally, they demonstrate remarkable damping capabilities, with a damping capacity of 91.2% and a peak tan δ of 1.11. Furthermore, the entropy‐driven rearrangement of ion‐dipole interactions ensures the damping properties of the SICE remain stable even at elevated temperatures (18–200 °C, with tan δ > 0.3), making it the most thermally resistant damping elastomer reported to date. Moreover, the SICE proves effective in filtering out various noises during physiological signal detection and strain sensing, highlighting its vast potential in flexible electronics. [ABSTRACT FROM AUTHOR]

Copolymerization stands as a versatile and potent method for tailoring polymer properties by adjusting structural unit composition and sequence distribution. However, achieving sequence‐controlled copolymerization in a one‐step and one‐pot process remains challenging. This study introduces a solvent‐dependent sequence‐controlled copolymerization strategy to produce block and statistical copolyesters from 4‐phenyl‐2‐oxabicyclo[2.1.1]hexan‐3‐one (4Ph‐BL) and ϵ‐caprolactone (ϵ‐CL). The distinct kinetics of the two monomers enable the facile synthesis of diblock and triblock copolyesters, PCL‐b‐P(4Ph‐BL) and P(4Ph‐BL)‐b‐PCL‐b‐P(4Ph‐BL), in non‐coordinating solvents, such as dichloromethane and toluene. Conversely, coordinating solvents like tetrahydrofuran, 2‐methyltetrahydrofuran, 2,5‐dimethyltetrahydrofuran, 1,4‐dioxane, and 1,2‐dimethoxyethane facilitate frequent transesterifications, yielding statistical copolyesters P[CL‐stat‐(4Ph‐BL)] with varying ratios of heterosequences. Density functional theory (DFT) calculations confirmed that coordinating solvents stabilize the transition state for transesterification, thereby validating their role in triggering this process. By varying the microstructures and compositions, the resultant copolyesters display tunable thermal and mechanical properties, evolving from robust plastics with an ultimate tensile strength of up to 46.3±3.1 MPa to tough elastomers with >99.3 % elastic recovery. All the copolyesters exhibit remarkable thermal stability (Td,5%=376 °C) and maintain desirable chemical circularity (>92 %), supporting a closed‐loop life cycle for sustainable material economy. [ABSTRACT FROM AUTHOR]

Soft strain sensors can accurately monitor the deformation of irregular and dynamic surfaces. However, traditional thin‐film strain sensors are generally not direction‐specific, and the sensor becomes unpredictable when stretched in different directions simultaneously. Here, a soft 1D strain sensor is reported that is only sensitive to axial deformation by rolling up a thin‐film strain sensor based on liquid metals (LM) and thermoplastic polyurethane (TPU) elastomer. The sensitivity of the 1D sensor can be regulated by rolling the 2D sensor at different angles. The 1D strain sensors have a large strain measuring range (>100%), high strain resolution (0.5%), fast responsiveness (<40 ms), and high reproducibility (over 2000 cycles), which are expected to adapt to various application scenarios with different sensitivity requirements. In addition, 1D strain sensors with different sensitivities can be braided into a three‐strand braid to provide measurements with three different sensitivities at the same time. [ABSTRACT FROM AUTHOR]

Through anionic two‐stage polymerization, block‐type styrene‐butadiene rubber (SSBR) with systematically regulable low‐temperature loss peaks is successfully prepared. The influence of 1,2‐Bd unit in the soft segment of block‐type SSBR on mechanical properties, dynamic mechanical properties, and microscopic morphology is studied, while pressure factors are introduced into dynamic mechanical studies. The block‐type SSBR with a soft segment containing 21.9 wt% of 1,2‐Bd exhibits the highest tensile strength, elongation at break, and tear strength. Under atmospheric pressure, the soft segment 1,2‐Bd unit influences the dynamic mechanical properties by altering the chain segment's motion loss capability. As the mass fraction of 1,2‐Bd increases from 21.9 to 58.6 wt%, tanδmax increases, the glass transition temperature of the soft segment increases from −59.0 to −18.9°C. Additionally, influenced by thermodynamic compatibility, the microscopic morphology transitions from strong separation to weak separation. Pressure affects dynamic mechanical properties by altering the free volume of the chain segments. Pressure reduces tanδmax, increases Tg, and raises the average Tg of the soft segment by 11°C. The K value of the linear equation representing the relationship between the soft segment Tg and the mass fraction of 1,2‐Bd is unaffected by pressure. [ABSTRACT FROM AUTHOR]

Thermoset materials, known for their stable topology structure, have garnered significant interest in recent years for their applications in coatings, foam, adhesives, and other fields. In general, the low chemical crosslinking density of thermoset materials means poor mechanical properties. In this study, we adjusted the topological structure of thermoset elastomers through formula design and controlled their hard segment content at the same level. The mechanical tensile test results show that as the chemical crosslinking density of the elastomer decreases, the fracture tensile strength shows a trend of first increasing and then decreasing. Although the content of amino ester groups in the elastomer is the same, low field nuclear magnetic resonance and Fourier transform infrared analysis show that as the density of the chemical cross‐linking network decreases, more physical cross‐linking points are formed between the elastomer network chains. Furthermore, the polyurethane hard segment formed an amorphous microphase separation structure in the elastic matrix. This study proves that constructing a moderate physical hydrogen bonding association structure between the network chains in polyurethane cross‐linked thermoset elastomers is another important way to prepare thermoset elastomers with excellent mechanical properties. [ABSTRACT FROM AUTHOR]

Amid the ongoing Global Plastics Treaty, high-quality circulation of halogen-containing plastics in an environmentally sound manner is a globally pressing issue. Current chemical dechlorination methods are limited by their inability to recycle PVC at the long-chain carbon level and the persistence of eco-toxic organochlorine byproducts. Herein, we propose a click dechlorination strategy for transforming waste PVC into valuable vitrimers via a one-step cascade thiol-ene click reaction and dynamic polymerization. Thermal activation of C-Cl bonds initiates β-elimination dechlorination, while disulfide bonds synchronously undergo homolytic cleavage, generating sulfur-centered radicals that drive precise sulfur-chlorine substitution and the formation of disulfide dynamic networks. This strategy achieves nearly complete chlorine extraction (93.88%) and produces vitrimers with tailorable mechanical and reprocessing properties, spanning from soft elastomers with 784% elongation to rigid plastics with a yield strength of 34 MPa. The significant advantage of this strategy is backbone protective precise dechlorination, enabling ecosystem toxicity reduced by 99.51% compared with widely adopted pyrolysis methods. This work introduces a sustainable pathway for upcycling PVC into valuable materials, marking significant progress in chlorinated plastic recycling. Current chemical dechlorination methods are limited by their inability to recycle PVC at the long-chain carbon level and the persistence of eco-toxic organochlorine byproducts. Here, the authors propose a click dechlorination strategy for transforming waste PVC into valuable vitrimers via a one-step cascade thiol-ene click reaction and dynamic polymerization. [ABSTRACT FROM AUTHOR]

Mechanochromic functionality realized via the force‐responsive mechanophores in polymers has great potential for damage sensing and information storage. Mechanophores with the ability to recognize multiple stimuli for tunable chromic characteristics are highly sought after for versatile sensing ability and color programmability. Nevertheless, the majority of mechanophores are based on single‐component chromophores with limited sensitivity, or require additional fabrication technology for multi‐modal chromism. Here, we report a novel multifunctional mechanophore capable of vividly detectable and tunable mechanochromism in polymers. This synergistic optical coupling relies on strategically fusing rhodamine and spiropyran (Rh−SP), and tethering polymer chains on both subunits. The mechanochromic behaviors of the Rh−SP‐linked polymers under sonication and compression are thoroughly evaluated in response to changes in force and the light‐controlled relaxation process. Non‐sequential ring‐opening of the two subunits under force is identified, endowing high‐contrast mechanochromism. Light‐induced differential ring‐closing reactions of the two subunits, together with the acidichromism of the SP moiety, are employed to engineer elastomers with programmable and wide‐spectrum colors. Our work presents an effective strategy for highly appreciable and regulable mechanochromic functionality, and also provides new insights into the rupture mechanisms of π‐fused mechanophores, as well as how the stimuli history controls stress accumulation in polymers. [ABSTRACT FROM AUTHOR]

This research paper proposes a unique way to safeguard delicate systems on submerged platforms from the undesirable effects of underwater explosion shock loads. The underwater detonation of an explosive charge and mines produce devastating underwater shocks against underwater platforms. Shock load developed underwater has been analyzed, and a shock response spectrum (SRS) approach to compute shock peak responses has been adopted. SRS shock absorption frequency satisfies requirements for both shock absorption and delicate systems. The shock load was reduced to 2g by altering the delicate system stiffness and damping properties. The analytical model for a single DOF system was formulated, and simulation was carried out using ANSYS solver. The stiffness has been spread across various points along the length of the delicate system, allowing it to undergo translational oscillations when subjected to shock loads. This research paper presents an innovative design approach for a shock absorption system intended for underwater sensitive objects, emphasizing simplicity, distinctiveness, compactness, reliability, and electromagnetic compatibility. Experimental testing validated the shock absorption design on the prototype. Shock testing determined the absorber's maximum displacement and sensitive object acceleration. [ABSTRACT FROM AUTHOR]

Sandwich structures are widespread in engineering applications because of their advantageous mechanical properties. Recently, their acoustic performance has also been improved to enable attenuation of low-frequency vibrations induced by noisy environments. Here, we propose a new design of sandwich plates (SPs) featuring a metamaterial core with an actively tunable low-frequency bandgap. The core contains magnetorheological elastomer (MRE) resonators which are arranged periodically and enable controlling wave attenuation by an external magnetic field. We analytically estimate the sound transmission loss (STL) of the plate using the space harmonic expansion method. The low frequency sound insulation performance is also analyzed by the equivalent dynamic density method, and the accuracy of the obtained results is verified by finite-element simulations. Our results demonstrate that the STL of the proposed plate is enhanced compared with a typical SP analog, and the induced bandgap can be effectively tuned to desired frequencies. This study further advances the field of actively controlled acoustic metamaterials, and paves the way to their practical applications. [ABSTRACT FROM AUTHOR]

Monodomain liquid crystal elastomers (LCEs) are prepared using liquid crystal block copolymers (LCBCPs) comprised of a nematic liquid crystal (NLC) main‐chain polyester linked to cross‐linkable polymethacrylate (PMA) at both ends. LCBCPs at a PMA weight fraction of ≈30% are doped with a tetra‐thiol compound, stretched in one direction, and then illuminated by UV light, yielding LCBCPs that formed microlamellae consisting of alternate stacking crosslinked PMA blocks and NLC polyester blocks. The LC director lay along the stretching direction (SD). Raising the temperature to the NLC isotropization temperature, the crosslinked LCBCP strips fixed at one end contracted reversibly by a factor of 1.2–1.4 along the SD, deforming the microlamellae. The strips fixed at both ends increased the tensile stress to ≈200 kPa while maintaining the microlamellae undeformed. Regardless of strip fixation at one or both ends, the NLC decreased the orientational order. The contraction amounts and the tensile stress of strips are well associated with decreased NLC orientational order. [ABSTRACT FROM AUTHOR]

In composite materials consisting of silver particles and a polypropylene matrix, the silver must migrate to the surface of the materials in order to exert on antibacterial effect. Substrates with various crystal structures may have different interactions with the silver particles, which can significantly impact the antibacterial performance. The research described in this paper investigates the influence of silver particles on the crystallization behavior of materials with varying crystallinity capabilities by selecting various polypropylene-based plastics and elastomers (Homopolymer polypropylene (PPH-T03), random poly(propylene/ethylene) copolymers (PPR-YPR503 and PPR-P340R), polyolefin elastomers (VERSIFY3000 (POE-1) and VERSIFY3401 (POE-2)), and ethylene propylene diene monomer for polymers (EPDM4725 and EPDM4770)). The research results indicated that the silver only entered the amorphous regions of the PP rather than entering the crystal regions, where they can more easily migrate to the material surface, resulting in a higher antibacterial effect. Therefore, the antibacterial degree of PP-Ag was as high as 99.9%. Silver can enter the micro-crystals of both the random copolymer polypropylene, (PPR-YPR503, PPR-1) and the random copolymer polypropylene, (PPR-P340R, PPR-2,) with a stronger effect on PPR-2. More silver entered the micro-crystals of PPR-2, and it was difficult for the silver ions to migrate out of the crystalline regions to exhibit antibacterial properties. The antibacterial degree of PPR-1-Ag was higher than that of PPR-2-Ag (77.8% vs. 66.7%). Similarly, silver had a greater impact on the lamellar structure of the polyolefin elastomer (VERSIFY3401, POE-2) compared to the polyolefin elastomer (VERSIFY3000, POE-1). In comparison with POE-2-Ag, POE-1-Ag exhibited a higher antibacterial degree (79.6% vs. 57.4%). Research on the two types of ethylene propylene diene monomer (EPDM) composite materials indicated that EPDM-1 exhibited a lower Mooney viscosity and poorer flowability. The EPDM-1 tended to encapsulate the silver within its molecular chains, thereby impeding the migration of silver to the surface. The optical performance analysis indicated that silver antibacterial agents had little impact on the optical properties of PP-Ag, PPR-1, PPR-2, POE-1, POE-2 and the EPDMs. We suggest that this research provides theoretical guidance for selecting highly antibacterial polypropylene materials. [ABSTRACT FROM AUTHOR]

The growing population of urban areas results in the need to deal with the noise pollution from the transportation system. This study presents experimental test results of static and dynamic elastic characteristics of under slab mats (USMs) according to the procedure of DIN 45673-7. Prototype USMs based on recycled elastomeric materials, i.e., SBR granules and fibres produced from waste car tires, are analysed. Vibration isolation mats with different thicknesses (10, 15, 20, 25, 30, and 40 mm), densities (500 and 600 kg/m3), and different degrees of space filling (no holes, medium holes, large holes) are considered. Moreover, a practical application of the laboratory test results of USMs in the design of ballastless track structures of two different types (with a concrete slab and longitudinal beams) is presented. Deflections of the rail and the floating slab system, as well as stresses acting on the mat, are determined according to EN 16432-2. The use of shredded rubber from recycled car tires as a material component of sustainable and environmentally friendly tram track structures may be one of the most effective ways to manage rubber waste within the current trend toward a circular economy, and this study intends to introduce methods for experimental identification and analytical selection of basic static and dynamic parameters of prototype USMs. [ABSTRACT FROM AUTHOR]

Side-chain liquid crystal polymers have been mixed with ferromagnetic particles, and the formation of a monodomain in magnetic fields studied. At relatively low concentrations, the presence of ferroparticles substantially speeds up the rate of formation of a monodomain within the magnetic field, and, at a given concentration of ferroparticles, that rate is independent of the magnetic field's strength. In this way, the rapid formation of a monodomain is possible at magnetic field strengths far lower those required for the liquid crystal polymer alone. This is anticipated to be very helpful in the fabrication of devices based on monodomain liquid crystal elastomers. Wide-angle x-ray scattering has been used to monitor the formation of the monodomain and small-angle x-ray scattering gives some indication of the ferroparticles' behaviour. A model is developed to explain their behaviour. The alignment properties of the ferroparticles are related to their ability to form chains under the influence of very low magnetic fields; these chains are of relatively low stability and may become disrupted after long periods of time, high magnetic fields, or high concentrations. In general, the best results for alignment were at volume fractions below 1%, and under these conditions there is the potential for producing monodomain samples with improved properties; in particular, shape changes with temperature are significantly larger as a result of improved backbone orientation. Experiments involving monodomain formation and director realignment suggest that the presence of ferroparticles results in a modification of the mechanism for alignment development, driven by the organization of the polymer backbone, as a consequence of the constraints offered by the morphology of the chains of the ferroparticles. [ABSTRACT FROM AUTHOR]