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Self-healing conductive elastomers have been widely used in smart electronic devices, such as wearable sensors. However, nano fillers hinder the flow of polymer segments, which make the development of conductive elastomer with rapid repair and high ductility a challenge. In this work, thioctic acid (TA) was grafted onto amino-modified polysiloxane (PDMS-NH2) by dehydration condensation of amino group and carboxyl group. By introducing gold nanoparticles, a dynamic network based on S-Au interaction was constructed. The dynamic gold cross-linking could effectively dissipate the energy exerted by external force and improve the extensibility of conductive elastomer. In addition, S-Au interaction had a good optothermal effect, so that the elastomer rapidly healed under NIR irradiation, and the repair efficiency reached 92%. We further evaluated the performance of the conductive elastomer as a strain sensor. The sample could accurately monitor the bending of human joints and small muscle state changes. This kind of self-healable conductive elastomer based on dynamic S-Au interaction has great potential in the fields of interpersonal interaction and health monitoring.

In this work, the corrosion behavior of medium-carbon steels (45, 45Cu and 45Cuq steels) in acidic chloride environment was investigated. The results indicated that the micro-galvanic effect between the anodic ferrite matrix phase and the cathodic cementite secondary phase notably affected the corrosion resistance of the three steels. For 45 steel, serious pitting corrosion happened in and around the pearlite regions, and a large number of lamellar cementite was fixed in the corrosion pits. Meanwhile, the continuously increasing superficial area of cathodic cementite enhanced the micro-galvanic corrosion, resulting in a rapidly increase in corrosion rate with time. While for 45Cu and 45Cuq steels, macroscopic uniform corrosion occurred, and the cementite accumulation was markedly reduced as compared with 45 steel, thus the micro-galvanic effect was weakened and the corrosion rate was decreased accordingly. Among these, 45Cuq steel showed the most stable and excellent corrosion resistance during long-term corrosion, indicating the occurrence of a synergistic effect between cementite spheroidization and Cu alloying, thereby significantly improving the corrosion resistance of 45 steel.

In this work, the beneficial effect of Sn addition on the corrosion resistance mechanism of Cr–Mo low alloy steel was studied. Results demonstrated that Sn improves the corrosion resistance of the steel matrix mainly by influencing the microstructural transformation. Sn addition and the synergistic effect of Sn, Cr, and Mo promote the formation of α-FeOOH, SnO2, SnO, Cr(OH)3, and molybdates, lead to the improved protection and stability of the rust layer. This synergistic effect also endows the inner rust layer with cation selectivity, preventing the further penetration of Cl− and inhibiting the localized corrosion of steel.

The corrosion behavior of the as-received steel and the spheroidized steel in acidic chloride environment was investigated. The results indicate the corrosion mode and corrosion rate of two steels are diverse due to their difference in microstructure. For as-received steel with ferrite-pearlite microstructure, severe localized corrosion happens on the pearlite regions, and plenty of cathodic cementite remains in the pits, further strengthening the micro-galvanic effect and accelerating the corrosion rate. While for spheroidized steel with tempered martensite microstructure, the nanosized cementite particles evenly distributed on the ferrite substrate are easy to fall off, which can significantly reduce the cementite accumulation on the steel surface, relieving the acceleration effect of micro-galvanic corrosion.

Background Asthma has been regarded as an inflammatory disease, and group 2 innate lymphoid cells (ILC2s) are implicated in asthma pathogenesis. However, no strategy is available to block ILC2s function. Efficiency is also limited due to the use of systemic or subcutaneous routes of administration. The purpose of this study was to investigate the effects of nanoparticles targeting suppression of tumorigenicity 2 (ST2), which is the ILC2 receptor, to alleviate lung inflammation in the murine model of asthma. Methods The ultra-small SPIO nanoparticles were firstly synthesized, OVA-induced mice were administered by anti-ST2-conjugated nanoparticles. The inflammatory degree of the lung was investigated by H&E. The percentages of ILC2s and CD4+T cells in bronchoalveolar lavage fluid (BALF) and lung tissue were determined by FACS. Th2-cytokine and OVA-IgE levels were detected by real-time PCR and ELISA, respectively. Results Treatment with anti-ST2-conjugated nanoparticles significantly alleviated airway inflammation, IL-33 and IL-13 levels and the percentage of CD4+T cells. The percentage of ILC2s was increased, whereas the levels of IL-13 and IL-5 expressed by ILC2s were reduced. Conclusion In the present study, we demonstrated that anti-ST2-conjugated nanoparticles can efficiently control lung inflammation in OVA-induced mice by reducing the ability of ILC2s to produce IL-5 and IL-13, thereby reducing CD4+T cells. Our study also demonstrated that the nanoparticle delivery system could improve the performance of anti-ST2, which may be used as a strategic tool to expand the current drug market.

Flexible conductive composites can be used as wearable strain sensors, which are widely used in the fields of new-generation robotics, electronic skin, and human detection. However, how to make conductive composites that simultaneously possess flexibility, stretchability, self-healing, and sensing capability is challenging research. In this work, we innovatively designed and prepared a silicone polymer conductive composite. MXenes and amino poly(dimethylsiloxane) were modified by small biomolecules via an esterification reaction and a Schiff base reaction, respectively. The modified MXenes are uniformly dispersed, which endows the composite with good electrical conductivity. The reversibility of multiple hydrogen bonds and imine bonds in the composite system makes it have ideal tensile properties and high-efficiency self-healing ability without external stimulation. The conductive composite containing 10 wt % A-MXenes showed an elongation of 81%, and its mechanical strength could reach 1.81 MPa. After repair, the tensile properties and the electrical conductivity could be restored to 98.4 and 97.6%, respectively. In addition, the conductive composite is further evaluated for the value of wearable strain sensors. Even after cut-healed processes, the conductive composite can still accurately detect tiny human movements (including speaking, swallowing, and pressing). This kind of self-healing MXene/PDMS elastomers based on the modification of small biomolecules has great potential as wearable strain sensors. This simple preparation method provides guidance for future multifunctional flexible electronic materials.

Ethyl acetate is a vital chemical raw material and is usually produced by esterification in industry. But this reaction can produce multiazeotrope mixtures of ethyl acetate/ethanol/water. In this work, triple column pressure-swing distillation process with and without heat integration and hybrid processes combining extractive distillation and pervaporation are proposed to separate a mixture of ethyl acetate/ethanol/water. Furthermore, the three processes are comprehensively compared with the triple-column extractive distillation process. Based on minimization of the total annual cost, the parameters of the all processes are optimized. The triple-column extractive distillation process has the greatest economic advantage. Additionally, the performances of the all processes in environmental protection and energy efficiency are evaluated. The energy efficiency of the combined extractive distillation and pervaporation unit process is relatively low, but its environmental impact is the lowest among the four processes.

Self-healing materials, which can autonomously repair damages like living organisms, have undergone extensive development in the last decades. The bottleneck problems for their practical applications are long healing time, inferior mechanical strength, and aging sensitivity. Here, a new class of polymeric materials rationally grafted with oligo poly(ethylene glycol) is reported. The network based on the formation of multiple weak hydrogen bonds endows the elastomers with good comprehensive performances including high stretchability (725%), high strength (4.20 MPa), and fast self-healing process (40 s). Benefiting from characteristic multiple weak hydrogen bond interactions, the fractured elastomers maintain high healing efficiency even after aging for 192 h, showing an unusual aging insensitivity. A Sudoku structural device based on the developed elastomer shows shape memory effect, providing a new avenue for fabricating novel smart devices with complicated shapes.

n-Propanol, as an important chemical raw material, is used as a solvent and intermediate in chemical industrial production and drug synthesis. In chemical production, alcohol and water easily form ...

In this study, a common-path compensation method is proposed for the laser beam drift resulting from the air parameters to enhance the stability of small-angle measurement in laser autocollimation....

Extractive distillation is a common method to separate the mixture, which has the low relative volatility. Many solvents were screened to separate the mixture based on the experiment. Because the n...

Typical autofocusing approaches have been proposed for digital holography (DH) to ascertain the peaks or valleys of critical functions. However, the sensitivity near the peaks or valleys is very low, which increases the difficulty of determining the best focusing position. This paper proposes a novel and fast focus plane detection method based on a virtual differential optical path, in which two virtual differential detectors are employed along the direction of the optical axis. One of the virtual detectors is located before the real detector and the other is behind it. This feature allows users to obtain two ordinary critical curves and a differential autofocusing curve (DAC). To determine the best focusing plane, the zero-crossing point of DAC is utilised. Mathematical models of the proposed method are developed, and numerical simulations and optical experiments are demonstrated to verify its feasibility. Results of industrial and biomedical objects demonstrate that the proposed method has good sensitivity and computational efficiency compared to traditional methods. To the best of our knowledge, this is the first time that the virtual differential optical path has been exploited for DH.

The self-healing and stretchable polyacrylate oligomers based on multivalent urea bonds were synthesized through the cross-linking of polyacrylate prepolymers and polyurea trimer. The variable temperature FT-IR and oscillatory rheometer analysis testified the excellent repeatability of multivalent urea bonds. Good thermal stability of the self-healing samples were proved by TGA. The length of the polymer branch and crosslink density of each sample could provide different thermodynamic properties which were confirmed by DSC and DMA. Meanwhile, the cross-linked polyacrylate oligomers without any catalyst or external intervention showed multiple self-repairs, scratch repair capabilities and high self-healing efficiency which was confirmed by the optical microscopy and the stress–strain testing. The maximum tensile strength of the pristine sample was as high as 7.8 MPa. Moreover, the oligomers showed self-repair repeatedly at room temperature and rapidly restored to 95% of the original tensile strength at 50 °C. Thus, the type of cross-linked polyacrylate oligomers might have high potential for further research in medicine, resin and plastics applications.

A new gemimi-like surfactant (named C14-N6-C14) formed by a mixed system of itaconic acid tetradecyl ester (C14) and 1,6-hexamethylenediamine (N6) at a molar ratio of 2:1 was developed to investigate the transition mechanism of pH-tunable wormlike micelles. pH-tunable properties of gemini-like surfactant were characterized by macroscopic observation, rheology, and 1H NMR measurements. The experimental results indicated that the pH-tunable properties could be ascribed to different protonation degrees and noncovalent interactions of the diamine to carboxyl groups of C14 at different pH values. The gemini-like surfactant C14-N6-C14 could be changed into itaconic acid monosodium salt surfactant (C14-ONa) when the pH was high enough. The formation of wormlike micelles was a result from the synergy between "gemini" and "unimer". In addition, the pH-tunable mechanism of the C14-N6-C14 system was proposed and further confirmed by mesoscopic morphological simulations using the dissipative particle dynamics (DPD) modul. The simulation and experimental results showed a good consistency, revealing the formation and destruction processes of wormlike micelles in the long chain acids and short amines mixed system. Our studies have lighted new views on understanding of the noncovalent interactions behind the structural changes by experiments and DPD simulation.

In recent years, lensfree on-chip microscopy has developed into a promising and powerful computational optical microscopy technique that allows for wide-field, high-throughput microscopic imaging without using any lenses. However, due to the limited pixel size of the state-of-the-art image sensors, lens-free on-chip microscopy generally suffers from low imaging resolution, which is far from enough to meet the current demand for high-resolution microscopy. Many pixel super-resolution techniques have been developed to solve or at least partially solve this problem by acquiring a series of low-resolution holograms with multiple lateral sub-pixel shifting or axial distances. However, the prerequisite of these pixel super-resolution techniques is that the propagation distance of each low-resolution hologram can be obtained precisely, which faces two major challenges. On the one hand, the captured hologram is inherent pixelated and of low resolution, making it difficult to determine the focal plane by evaluating the image sharpness accurately. On the other hand, the twin-image is superimposed on the backpropagated raw hologram, further exacerbating the difficulties in accurate focal plane determination. In this study, we proposed a high-precision autofocusing algorithm for multi-height pixel-super-resolved lensfree on-chip microscopy. Our approach consists of two major steps: individual preliminary estimation and global precise estimation. First, an improved critical function that combines differential critical function and frequency domain critical function is proposed to obtain the preliminary focus distances of different holograms. Then, the precise focus distances can be determined by further evaluating the global offset of the averaged, low-noise reconstruction from all backpropagated holograms with preliminary focus distances. Simulations and experimental results verified the validity and effectiveness of the proposed algorithm.

In this paper, we consider a nonautonomous predator–prey model with Holling type II schemes and a prey refuge. By applying the comparison theorem of differential equations and constructing a suitable Lyapunov function, sufficient conditions that guarantee the permanence and global stability of the system are obtained. By applying the oscillation theory and the comparison theorem of differential equations, a set of sufficient conditions that guarantee the extinction of the predator of the system is obtained.

Preparing non-noble metal and metal-free electrocatalysts as the alternatives to noble metal-based materials, such as Pt/C, IrO2, is very necessary for energy conversion and storage. Carbon-based nanomaterials are promising candidates because of their low-cost, good electrical conductivity, and high surface area. Among the carbon nanomaterials, graphene and carbon nanotube are more excellent as the electrocatalysts for oxygen electrode reactions, especially heteroatoms doped graphene and carbon nanotube. Herein, we developed a bifunctional electrocatalyst composed of nitrogen, sulfur co-doped graphene oxide and multi-walled carbon nanotube (N, S-GCNT), which exhibit good performance for catalyzing oxygen reduction and evolution reactions. These properties are comparable to those of noble-based catalysts such as Pt/C and IrO2, which are attributed to the synergetical effect of doped N, S because they modified the polarity of carbon in the graphene and carbon nanotube. This work provides a simple way to prepare high performance carbon-based metal-free catalysts for the applications in energy-related reactions.

Due to the deterioration of the environment, the environmental protection has received more and more attention from the world. Various countries have established regulations to strictly limit the emission of organic volatiles (VOC) in paints. Solvent-based paints contain a large amount of VOC components, which not only pollutes the environment and wastes resources but also endangers people's health. Waterborne polyester coatings as representative waterborne coatings have become the development direction of coatings. In this study, a novel waterborne unsaturated polyester was synthesized by melt polycondensation and its water solubility was regulated by changing the amount of sodium sulfonate group. Then, a series of UV curable polyester networks were obtained utilizing the waterborne unsaturated polyester and multifunctional thiols via thiol–ene click reaction. The water resistance, gel content and mechanical properties of the films were characterized. It was found that the UV-cured films exhibited excellent physical properties including adhesion (1), pencil hardness (5 H), water resistance and contact angle (105.36). This shows that it is feasible to prepare high-performance UV-cured films based on thiol-ene click chemistry.

The use of starch as renewable resource to produce eco-friendly hybrid latex has received an increasing attention in industrial application. In this work, enzymatically hydrolyzed starch-graft-poly(n-butyl acrylate-co-methyl methacrylate) (ES-g-P(BA-MMA)) latexes were synthesized by seeded surfactant-free emulsion polymerization. A complex initiation system was used to enhance the grafting efficiency. The mechanisms of initiation and graft copolymerization were discussed. The ES-g-P(BA-MMA) latexes were characterized by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electronic microscopy (TEM), and differential scanning calorimetry. The effect of reaction condition on graft copolymerization was investigated. The evolution of particle morphology was revealed by the TEM. The ES-g-P(BA-MMA) latexes were used as binders for paper coating. The strength-related properties of coated paper were evaluated. The results showed that the folding resistance and picking resistance were improved. All the other properties were at least equally good as in the reference sample. The crosslinked ES-g-P(BA-MMA) latex was more effective in improving properties. The folding resistance and wet tensile strength index were enhanced significantly by 29.5% and 36.6%, respectively. This study provides an alternative choice for paper coating to develop coated paper with better properties.

The non-isothermal crystallization behavior of poly (butylene succinate) (PBS) modified by magnesium hydroxide sulfate whisker (MHSH) was studied by means of differential scanning calorimetry (DSC). Crystallization exotherms were recorded at four different cooling rates, i.e., 5, 10, 15, and 20 °C/min. Crystallization parameters were analyzed using Avrami method modified by Jeziorny, Mo models and Friedman’s isoconversional method modified by Vyazovkin to evaluate the effective activation energy. Nucleation ability of MHSH was evaluated by employing polarizing optical microscopy (POM). Kinetics studies reveal that MHSH can act as an efficient nucleating agent for the crystallization of PBS. With MHSH addition increasing, the rates of nucleation and growth of PBS are obviously increased. Further analysis of the above models shows that the MHSH does not change the nucleation mechanism and crystal growth of PBS, but decreases the crystallization activation energy of PBS, which facilitates the crystallization of PBS.

The poly(N-isopropylacrylamide-co-N-maleylgelatin) [P(NIPAAm-co-N-MAGEL)] hydrogel was prepared by the free radical polymerization of N-isopropylacrylamide (NIPAAm) and N-maleylgelatin (N-MAGEL) with N,N′-methylene bis(acrylamide) (BIS) as the cross linker in the complete aqueous environment. The hydrogel becomes opaque when the temperature exceeds lower critical solution temperature (LCST) and goes back to its original transparent state when it is cooled below the LCST which can be finely tuned as it shows a linear dependence on the concentration of Na+, Mg2+ and Al3+. Interestingly, different from Na+ and Mg2+, Al3+ could mediate the transparency of the hydrogel even when the temperature is below LCST and induce the formation of double-network (DN) hydrogel. Metal-ion-carboxylate supramolecular interactions are proposed to dominate this property through ionic cross-linking. The hydrogel could be used as the temperature and metal ions controlled smart window. Effects of metal ions on swelling characteristics, mechanical property and microstructures of the hydrogel were further investigated.

A type of thiophene-bridged silica aerogel was prepared from tetraethyl orthosilicate (TEOS) and 2,5-divinyltrimethoxysilanethiophene (DVTHP) through a facile sol–gel reaction and ambient pressure drying process. DVTHP was synthesized from vinyl trimethoxysilane and 2,5-dibromothiophene through the Heck reaction. FTIR and solid-state 1H CP/MAS NMR indicated that the thiophene units had been successfully introduced into the silica aerogel network. SEM showed a co-continuous porous structure and the Brunauer–Emmett–Teller (BET) measurements showed a mesoporous structure that had a high surface area of 834 m2 g−1, an average pore size of 17.84 nm and a large pore volume of 3.72 cm3 g−1. This thiophene-bridged silica aerogel had superhydrophobicity with a water contact angle (CA) exceeding 174° and a sliding angle of less than 3°. The silica aerogel had better selectivities for less polar or non-polar solvents than for polar solvents. The introduction of the thiophene unit could improve the adsorption properties. The adsorption capacities for n-hexane and gutter oil were calculated as 17 g g−1 and 16 g g−1, respectively. Moreover, the samples exhibited good recyclability for organic solvents even after recycling 10 times in adsorption/desorption tests and the adsorption capacities were nearly unchanged from the maximum uptake capacities. The results indicated that these materials could be flexibly utilized as adsorbent materials to selectively adsorb organic solvents for wastewater treatment.

The development of antifouling biosensors capable of detecting biomarkers at low concentrations in complex bio-fluids with many interference components is of great importance in the diagnosis and treatment of diseases. Certain zwitterionic peptides composed of natural L-amino acids have been used for the construction of low fouling biosensors and demonstrated excellent antifouling performances, but they are prone to enzymatic degradation in biological media, such as serum that contains a variety of enzymes. In this work, a novel antifouling peptide with the sequence of cppPPEKEKEkek was designed, and three unnatural D-amino acids were set at both ends of the peptide to enhance its tolerance to enzymatic degradation. An electrochemical biosensor was constructed by coupling the antifouling peptide with a conducting polymer polyaniline (PANI) to achieve accurate detection of alpha-fetoprotein (AFP) in clinical samples. Owing to the presence of the designed peptide with partial D-amino acids (pD-peptide), the biosensing interface showed significantly high antifouling performance and enhanced stability in human serum. Meanwhile, the pD-peptide based biosensor exhibited high sensitivity toward the target AFP, with the linear range from 0.1 fg mL−1 to 1.0 ng mL−1 and the limit of detection of 0.03 fg mL−1 (S/N = 3). This strategy of enhancing the stability (tolerance to enzymolysis) of antifouling peptides in biological samples provided an effective way to develop antifouling biosensors for practical applications.

Electrochemical assays potentially offer a highly cheap, automated, portable and sensitive method for a great deal of disease biomarker detections, and minimization of nonspecific adsorption is a critical issue for their application in natural complex media. We present herein, the development and application of a highly sensitive and selective electrochemical DNA hybridization biosensor for breast cancer marker BRCA1, based on a zwitterionic peptide self-assembled monolayer (SAM) support serving as the low fouling substrate, the 19-mer BRCA1 related sequence-specific oligonucleotides, and the sensitively label-free sensing technique of electrochemical impedance spectroscopy (EIS). The capability of such peptide SAM in resisting nonspecific protein adsorption was surveyed using EIS, and the biosensor fabrication process and sensing performance were also investigated with X-Ray photoelectron spectroscopy (XPS) and EIS. Significantly, this developed biosensing strategy achieved a linear detection range from 1.0 fM to 10.0 pM with a limit of detection of 0.3 fM, associated with satisfactory sensing properties of facile fabrication, desired sensitivity, high selectivity, and favourable reproducibility and antifouling ability, manifesting its promising potential in practical application.

Poly(butylene succinate)/magnesium hydroxide sulfate hydrate whisker (MHSH) composites were prepared using the prepolymer from 1,4-butanediol, succinic acid, and modified MHSH, which were characterized by FTIR and 1H NMR. The thermal, crystallographic, and mechanical properties of the PBS composites were investigated. Differential scanning calorimetry (DSC) demonstrated that glass transition temperature (Tg) and crystallization temperature (Tc) were increased with increasing of filler content. The thermal degradation process of PBS composites was analyzed by TG-FTIR, and a possible thermal degradation mechanism of PBS was proposed. The results indicated that the prepolymer was better than UMHSH in interfacial adhesion with PBS. The tensile strength, flexural strength, and modulus were significantly increased with the addition of filler mass fraction, especially when the composites were blended with the prepolymer.

Bacterial resistance to antibiotics reduced the demand for antibiotics in the field of medical devices. Polymer antibacterial materials have shown great potential in the medical field. However, the treatment of materials after use is not environmentally friendly. Therefore, the development of dissoluble polymer antibacterial materials has become an urgent challenge. In this paper, an antibacterial polymer material with high self-healing ability and rapid dissolution is reported. The new material was formed by the Schiff base reaction and cross-linking of aldehyde group and amino in terephthalaldehyd (TA), 3,4-diaminofurazan (DAF) and α,ω-aminopropyl terminated polydimethylsiloxane (PDMS, Mn = 3000). The properties of the material were further enhanced by the coordination of zinc ion with nitrogen and oxygen atoms of 3,4-diaminofurazan. The antibacterial polymer material designed by us can be effectively repaired at 100 °C. The first repair efficiency was 89.5%. After repeated repair, its mechanical properties were not significantly reduced. E. coli and S.aureus were used to evaluate the antibacterial ability of the material. The antibacterial efficiency of the material was 99.9993% and 99.9997% respectively. This new idea solved the urgent problems in the current application, and provided guidance for the research of flexible antibacterial materials.

Waterborne polyurethane (WPU) prepolymer was synthesised by the reaction of poly(butylene itaconate) ester (PBI, Mn = 1109 g/mol), 1,6-hexanediol, dimethylol propionic acid (DMPA), 2,4-tolu...

A novel itaconate-based surfactant, namely sodium n-octyl sulfoitaconate diester (SOSID), has been synthesized from itaconic acid (IA) and n-octanol by sulfonation and esterification reaction processes. The effects of reaction temperature, reaction time, molar ratios of n-octanol to IA and the catalyst dosage on the esterification were investigated. The chemical structure of the surfactants SOSID was characterized by means of LC–MS and confirmed by FT-IR and 1H NMR spectroscopy. The surface tension γ and the critical micelle concentration (CMC) were determined as 25.02 mN/m and 4.0 × 10−4 mol/L by using surface tensiometer at 20 °C. Further investigations showed that SOSID possess excellent wetting, emulsifying and lime soap dispersing properties.

The morphology and aspect ratio of calcium sulfate hemihydrate (HH) are successfully controlled using AlCl3 as a morphology modifier in the hydrothermal synthesis process. As the concentration of AlCl3 is increased from 0 to 7.5 × 10−2 mol L−1, the crystal length decreases from 130 μm to 0.1–0.3 μm and the corresponding aspect ratio declined dramatically from 150–240 to 1–2, and the crystal morphology gradually changes from whiskers to rods, and even irregular nanogranules. The preferential adsorption of Al3+ on the side facets of HH would lower the surface energy and inhibit the elongation along these facets. The doping of Al3+ in the HH would destroy the main chain of HH and inhibit the elongation along the [001] direction. The two facts contribute to the morphology control. This work exhibits an efficient method to control the morphology of HH over a large range of size by simply adjusting the concentration of AlCl3.

Polymer materials with good mechanical properties, solubility and flexible self-healing conditions were of great value to the development of modern high-tech fields. Herein, α,ω-aminopropyl terminated polydimethylsiloxane (PDMS, Mn = 2000), terephthalaldehyd (TA) and 3-aminophenylboronic acid (APB) were used to construct a three-dimensional network via simple and effective reactions, such as the Schiff base reaction and the dehydration reaction. The obtained PDMS elastomer prepared by low molecular weight main chain could achieve very good mechanical performance of tensile strength 2.54 MPa and the average elongation at break of 275.3%. Through the dynamic imine bonds formed by Schiff base reaction and the coordination of boron oxygen bonds and hydrogen bonds, we have constructed a high efficiency self-healing network. The network could achieve self-healing at room temperature with a self-healing efficiency of 91.6%, at high temperature with a self-healing efficiency of 95.1% and in water at a self-healing efficiency of 85.5%. In addition, multi-walled carbon nanotubes (MWCNTs) was compounded with a polymer system to prepare self-healing flexible electronic devices. Due to the electric resistance of PDMS/MWCNTs sensitively modified with the change of tensile and bending angles, this might be of great significance for the application of sensors.

Herein, we report an innovative cross-linked network of silicone elastomer with good stretchability, thermal stability and autonomous self-healing. This type of elastomers was easily prepared by aminopropyl terminated polydimethylsiloxane (A-PDMS), thioctic acid (TA) and 2,6-pyridine dialdehyde (Py). As we know, TA was firstly incorporated into the reversible network of silicones to supply the dynamic disulfide bonds and endow the self-healing properties. Py was also introduced into the network which acted as the metal-ligand binding sites. Consequently, silicone elastomers with three different types of chemical interactions including the disulfide bonds, hydrogen bonds and metal-ligand bonds were obtained. Especially, they possessed good anticorrosion and strong adhesion affinity. We expected this type of silicone elastomers could be applied into the soft robotics, wearable electronics and stretchable circuit constructed.

In this study, a type of silicone modified styrene-acrylate latex (SSA) was synthesized by styrene (St), vinyl trimethoxysilane (VTMS) and isooctyl acrylate (IA) through RAFT emulsion polymerization. The molecular weight and distribution (PDI) of SSA increased with VTMS contents ranging from 0 to 4%. It also enhanced the tensile strength of SSA coatings from 3.6 to 5.8 MPa. Furthermore, SSA coatings possessed the good self-healing properties. TGA and DMA indicated the thermal stability of SSA coatings increased with the increasing of VTMS contents. It also increased the water contact angle (CA) from 85 to 105° and reduced the water absorption from 3.75 to 0.8%. The open circuit potential (Eocp)-time and anodic polarization (Tafel) curves indicated the corrosion resistance enhanced with the increase of the VTMS contents. The all obtained results indicated the SSA would have great potential as weatherable and anticorrosive coatings.

Carbon nanomaterials are potential materials with their intrinsic structure and property in energy conversion and storage. As the electrocatalysts, graphene is more remarkable in electrochemical reactions. Additionally, heteroatoms doping with metal-free materials can obtain unique structure and demonstrate excellent electrocatalytic performance. In this work, we proposed a facile method to prepare bifunctional electrocatalyst which was constructed by nitrogen, sulfur doped graphene (NSG), which demonstrate superior properties with high activity and excellent durability compared with Pt/C and IrO2 for oxygen reduction (OR) and oxygen evolution (OE) reactions. Accordingly, these phenomena are closely related to the synergistic effect of doping with nitrogen and sulfur by rationally regulating the polarity of carbon in graphene. The current work expands the method towards carbon materials with heteroatom dopants for commercialization in energy-related reactions.

The suppression of coherent noise can produce higher-quality reconstructed images in digital holographic microscopy. A robust and effective phase coherent noise denoising algorithm is proposed in this paper that combines the anisotropic diffusion equation and the phase quality map. In order to accurately identify the noise and signal pixels, we introduce the phase quality map and edge detection to quantify the quality of the pixel information. In addition, a synthetic diffusion function is established to control the speed of the anisotropic diffusion process based on the quality coefficient. Several experiments have been carried out to validate the effectiveness of the proposed algorithm for coherent noise reduction. The results demonstrate that the proposed algorithm can reduce coherent noise and preserve edge details well.

A novel type of fluorosilicone resin (FSR) based on trifluoropropylalkoxylsilane (T monomer) was synthesized using hydrolysis-polycondensation method and cured by hydrosilylation reaction. The molecular structure of FSR was characterized by FTIR and NMR spectra. The property of the cured FSR was also investigated. TGA/DTG showed the good thermal stability of the cured FSR because of no residual terminal hydroxyl groups in FSR molecular structure. The higher molar ratios of trifluoropropyl (-CH2CH2CF3) and methyl groups (F/R molar ratios) lowered the thermal stability. DSC results indicated the only one Tg of each cured FSR and it varied from −52.0 °C to −13.2 °C. Furthermore, the cured FSR possessed good mechanical properties that the tensile strength could exceed 2.0 MPa and the elongation at break was higher than 300%. The increase of F/R molar ratios lowered the surface free energy of the cured FSR from 24.20 mN/m to 22.98 mN/m which indicated the surface hydrophobicity improved. The water and n-hexadecane contact angles were 110.4° and 34.2° that might be attributed to the smooth surfaces characterized by SEM and AFM.

To accurately measure ultrasmall rotation angles, a robust and effective method based on lensless digital holographic microscopy is proposed in this paper. The method combines holographic microscopy, solid geometry, and 3D measurement, including holographic measurement and angle measurement processes. We can calculate the 3D shape by the angular spectrum algorithm and the least-squares phase-unwrapping algorithm in the holographic process. According to the relationship between the surface shape and rotation angles, the real-time rotation angles can be calculated. To validate the feasibility and practicability of the proposed approach, numerical noise simulations and experiments were performed. The measurement precision of rotation angle can reach 0.5″ in the range of 1000″ in this paper's experiments. The holographic method has high measurement precision and good stability. In addition, the compact small volume has great potential in small-angle sensor applications.

Herein, the feasibility of preparing long and homogeneous hemihydrate (HH) whiskers using waste oyster shell was investigated. The whiskers formed from the sintered raw material had higher aspect ratios and more uniform morphology than non-sintered. The effect of reaction temperature, reaction time, and concentration were investigated. It was found that the optimum reaction temperature, reaction time, and concentration for stable and well-grown whiskers were 140 °C, 5 h, and 4 wt%, respectively. Direct transition from calcium sulfate dehydrate (DH) to HH was detected by X-ray diffraction (XRD) patterns, and the result showed DH completely transformed to HH after 5 h. The preferred direction of growth along the c-axis was confirmed by XRD pattern, selected area diffraction pattern, and high-resolution transmission electron microscopy (HRTEM).

A sensitive and low-fouling aptasensor for alpha-fetoprotein (AFP) was developed based on mixed self-assembled aptamers and newly designed zwitterionic peptides, where densely immobilized peptides formed an antifouling layer to resist nonspecific protein adsorption, and sparsely attached aptamers acted as the recognizing layer to achieve target binding. The obtained biosensing interface responded to the target AFP with a strikingly selective and sensitive manner, exhibited excellent protein-resistant performance even in complex human serum solution, and showed promising feasibility for the quantitative analysis of AFP in real human serum samples.

A type of itaconic acid (IA) modified polyacrylate (PIA) was synthesized by ethyl acrylate (EA), ethyl methacrylate (EMA) and methyl methacrylate (MMA) as co-monomers through the emulsion polymerization. The chemical structure of PIA characterized by FTIR and 1H NMR manifested the successful introduction of IA into PIA chains. The increase of IA content increased the particle size from 101.9 to 327.6 nm and lowered the ZETA potentials from −42.5 to −68.1 mV, respectively. It enhanced the tensile strength and tensile modulus of PIA films from 8.5 to 11.4 MPa and 82 to 582 MPa with the IA content ranging from 0.5 to 2.5 wt%. Also, Tg raised from 6.8 °C to 17.9 °C due to the compact structure and rigidity of the chains. Moreover, TGA indicated the increased thermal stability of PIA as the increase of IA content. Foremost, MTT colorimetric test proved PIA had higher cell viability and ALT serum activity than the common coating materials in the market. In vivo toxicity test evaluated by the physiological responses of mice through the oral administration also illustrated PIA was innoxious and had good biocompatibility. The obtained results indicated PIA would have great potential as drug coating materials in the pharmaceutical industry.

The objective of this investigation is to liquefy peanut shell for the preparation of aromatic polyol-rich products. The influences of reaction parameters are discussed. It is found that, compared to single-solvent, the mixture of polyethylene glycol and glycerol as solvents shows higher liquefaction efficiency. And the maximum liquefaction yield of 98.7 wt % can be achieved when the sulfuric acid content, mass ratio between polyethylene glycerol, glycerol, and peanut shell powder, liquefaction temperature, and time are 17 wt % (relative to peanut shell), 8/2/1, 150 degrees C, and 2 h, respectively. Furthermore, the solubility test result indicates that the liquefied products are fully soluble in the water and polyol. Meanwhile, the properties of the peanut shell and liquefaction residue were analyzed by means of attenuated total reflectance-Fourier transform infrared spectroscope, thermal gravity analysis, and scanning electron microscope. The polysaccharide is degraded by the cleaving of C-O bond, and the lignin is decomposed by leaving the dominant linkages including beta-O-4, 4-O-5, and dibenzodioxocin units. The fibers in the peanut shell are broken, and the nondegraded components in the residue lost their network structure. (C) 2016 Wiley Periodicals, Inc.

Biocompatible polymers, such as poly(ethylene glycol) (PEG), are of great significance in the development of bio-interfaces and biosensors, as they possess excellent biocompatibility and are easy for modification. A novel highly biocompatible polymer composite was synthesized herein through electrochemical polymerization of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and a PEG derivative, 4-arm PEG terminated with thiol groups. The electrodeposited conducting polymer composite of PEG doped PEDOT (PEDOT/PEG) exhibited flake-like nanostructure, large surface area and outstanding stability. In order to further immobilize antibodies, gold nanoparticles (AuNPs) were introduced to the PEDOT/PEG composite surface through their unique interaction with the thiol groups. AuNPs modified PEDOT/PEG provided a desirable support for the immobilization of various biomolecules such as antibodies for alpha fetoprotein (AFP), a vital tumor biomarker for liver cancer. The fabricated AFP biosensor demonstrated favorable selectivity, high sensitivity, and ultralow detection limit. Furthermore, owing to the presence of PEG polymers that are highly hydrophilic, such AuNPs/PEDOT/PEG based AFP biosensor also exhibited good anti-fouling ability, and it was capable of assaying target AFP in 10% (V/V) human serum samples, indicating highly feasible potential for clinical diagnosis.

The bio-based rigid polyurethane (PU) foams were successfully prepared based on liquefied products from peanut shell with water as the blowing agent. The influence of reaction parameters on properties of rigid PU foams was investigated. Rigid PU foams showed excellent compressive strength and low shrinkage ratio, whereas their open-cell ratio and water absorption were higher. Therefore, rigid PU foams were synthesized with petroleum ether, diethyl ether, and acetone as auxiliary blowing agents and their inner temperature, shrinkage performance, density, compressive strength, water absorption, and open-cell ratio were determined. The results indicated that above rigid PU foams showed lower compressive strength than the original foam but their water absorption and close-cell ratio were improved. Compared with the original foam, the highest inner temperature of rigid PU foams with petroleum ether, diethyl ether, and acetone as auxiliary blowing agents was reduced by 11, 19, and 23 °C, respectively. Typically, foams with petroleum ether as auxiliary blowing agent displayed better water absorption and swelling ratio in water and exhibited obvious improvement in close-cell ratio. These foams were preferable for application in thermal insulation materials because of low thermal conductivity and better corrosion resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45582.