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Alkylated benzothienobenzothiophenes are an important class of organic semiconductors that exhibit high performance in solution-processed organic field-effect transistors. In this work, we study the near-edge x-ray absorption fine-structure (NEXAFS) spectra of 2,7-didecyl[1]benzothieno[3,2-b][1]benzothiophene (C10-BTBT) at both the carbon and sulfur K-edges. Angle-resolved experiments of thin films are performed to characterize the dichroism associated with molecular orientation. First-principles calculations using the density functional theory-based many-body x-ray absorption spectroscopy (MBXAS) method are also performed to correlate the peaks observed and their dichroism with transitions to specific antibonding molecular orbitals. Interestingly, the dichroism of the dominant, lowest energy peak is opposite at the carbon and sulfur K-edges. While the low-energy peak at the carbon K-edge is assigned to carbon 1s → π* transitions with transition dipole moment (TDM) perpendicular to the planar BTBT core, the dominant low energy peak at the sulfur K-edge is assigned to sulfur 1s → σ* transitions with TDM oriented along the long axis of the BTBT core. These differences at the sulfur and carbon K-edges are understood through the MBAXS simulations that find a reordering of the energy of the lowest energy π* and σ* transitions at the sulfur K-edge due to the strong localization of the σ* orbital over the sulfur atom. This work highlights differences in the NEXAFS spectra of organic semiconductors at carbon and sulfur K-edges and provides new insights into peak assignment and x-ray dichroism relevant for studying the molecular orientation of organic semiconductor films. [ABSTRACT FROM AUTHOR]

Second harmonic generation (SHG) is a nonlinear optical phenomenon where two photons at the frequency ω combine to form a single photon at the second-harmonic frequency 2ω. Since that second-order process is very weak in bulk isotropic media, optical SHG responses of interfaces provide a powerful and versatile technique to probe the molecular structure and dynamics of liquid interfaces. Both local dipole contributions and non-local quadrupole contributions can be interesting to investigate different properties of the interface, such as the molecular orientation or the charge density. However, a major difficulty is to comprehend the link between the S-SHG intensity and molecular details. This article reports a numerical approach to model the polarization-resolved SHG intensities of a model vapor/liquid interface of pure water. The influence of the interfacial local environment on the hyperpolarizability is taken into account using quantum mechanical/molecular mechanics calculations. The numerical predictions are in very good agreement with experiments. We detail the hypotheses made during the modeling steps and discuss the impact of various factors on the modeled SHG intensities, including the description of the exciting field in the interfacial layer, the effect of neighboring molecules on the second-harmonic polarization, and the presence of an additional static electric field at the interface. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamic behavior of EthylChlorophyllide A (EChlideA) molecules in a methanol solution confined within a 4 nm silica nanoslit, using molecular dynamics simulations over a duration of 1 ms. Three systems, containing 1, 2, and 4 solutes, were studied at 298 K. The results demonstrate that EChlideA molecules predominantly adsorb onto the silica surfaces, driven by specific interactions between chlorin ring's methyl group and the hydroxyl groups of the silica. This adsorption leads to stable binding, particularly in less crowded environments, as indicated by the potential of mean force analysis. Higher molecular concentrations, such as those with four EChlideA molecules, introduce variation in binding strength due to molecular aggregation and complex interactions. The orientation analysis reveals that the chlorin ring tends to align parallel to the surface, requiring rotational adjustments during surface diffusion. In addition, solvent coordination around the Mg ion remains consistent under bulk conditions, although with some variation in higher concentrations. This study also highlights a decrease in linear diffusion and an increase in rotational relaxation times for EChlideA molecules within the confined nanoslit, reflecting the influence of molecular concentration and arrangement on their dynamics. These findings provide valuable insights into the role of surface interactions, molecular orientation, and solvent coordination in confined environments, offering implications for the design of nanoscale systems. [ABSTRACT FROM AUTHOR]

The interfacial structure and adsorption behavior of 1-butyl-3-methylimidazolium thiocyanate ionic liquids (ILs) aqueous solutions were investigated using sum-frequency generation vibrational spectroscopy (SFG-VS) and surface tension measurements. Polarization-dependent measurements revealed a dramatic increase in the SFG signal for both CH and CN stretching modes with increasing ILs concentration, reaching a maximum at a mole fraction of 0.01. This concentration dependence was accompanied by a dramatic drop in surface tension. Upon further increasing the concentration, surface tension varied slightly and reached a constant value, while the SFG signal decreased significantly. Quantitative polarization analysis showed that as the bulk concentration increased, the apparent molecular orientation of the SCN− transition dipole at the interface changed from 51° to 46°, and the tilt angle of CH3 group of the butyl chain attached to the imidazole cationic ring changed from 18° to 32°. The decrease in the SFG signal can be explained by the formation of a double layer adsorption structure at the air/water interface. It was also demonstrated that the anions were adsorbed at the interface simultaneously with the cationic group, rather than by successive adsorption as proposed in a previous study. Using the Shereshefsky model, the thermodynamic Gibbs free energy of adsorption deduced from surface tension data was compared with SFG results. [ABSTRACT FROM AUTHOR]

We examine an algorithm for the creation of proton-disordered ice cells based on a simulated-annealing (SA) scheme for molecular orientations. Application to defect-free ice Ih, a clathrate-hydrate structure, and a random polycrystalline ice Ih sample demonstrates the SA technique to be effective, attaining maximum HB connectivity using relatively short cooling simulations, thus serving as an alternative method for those cases in which the application of topology-based methods is inhibited. [ABSTRACT FROM AUTHOR]

Water confined within nanochannels with specific functionalities serves as the foundation for a variety of emerging nanofluidic applications. However, the structure and dynamics of the confined liquid are susceptibly influenced by practically hard-to-avoid defects, yet knowledge of this fact remains largely unexplored. Here, using extensive molecular dynamics simulations, we elucidate the significant influence of geometric and charge defects on one-dimensional confined water. We show that the two types of defects can both reshape the water density distribution by constraining the translocation of water molecules along the circumferential direction. In addition to structural alterations, collective translocation and rotation of water slabs arise during transportation under external pressure. Below the temperature threshold marking the initiation of liquid-solid transition, the geometric defect retards water diffusion through a pinning effect, while the charge defect induces an anti-freezing effect. The latter is attributed to the electrostatic interaction between the charge defect and water molecules that hinders the formation of a stable hydrogen bond network by disrupting molecular dipole orientation. Consequently, this behavior results in a reduction in the number and lifetime of hydrogen bonds within the phase transition interval. The distinct roles of the two types of defects could be utilized to control the structure and dynamics of confined liquids that may result in distinct functionalities for nanofluidic applications. [ABSTRACT FROM AUTHOR]

The interplay between orientation transition and chiral self-assemblies of para-terphenyl (P3P) molecules on the Cd(0001) surface has been investigated using low temperature scanning tunneling microscopy and density functional theory calculations. Three distinct molecular orientations have been discerned from the self-assembled thin films of P3P. At the low coverage, flat-lying molecules appear in the homochiral domains with the incommensurate registry to the substrate. With the coverage increasing, the incoming molecules are incorporated into the first layer with edge-on orientation and form the self-assembled zigzag chains. The alternative arrangement of zigzag chains with opposite chirality leads to the formation of a c(4 × 2) superstructure, in which the tilted molecules exhibit orientational frustration and fuzzy noises. The analysis of the tunneling spectra reveals that the electronic structure of P3P layers is contingent upon the hybridization between the electronic states of P3P molecules and the Cd(0001) surface. These results provide important insights into the interplay between orientational transition and chiral assembly of P3P molecules on metal substrates. [ABSTRACT FROM AUTHOR]

The control of movement and orientation of gas-phase molecules has become the focus of many research areas in molecular physics. Here, ND3 molecules are polarized in a segmented, curved electrostatic guide and adiabatically aligned inside a rotatable mass spectrometer (MS). Alignment is probed by photoionization using a linearly polarized laser. Rotation of the polarization at fixed MS orientation has the same effect as the rotation of the MS at fixed polarization, proving that the molecular alignment adiabatically follows the MS axis. Polarization-dependent ion signals reveal state-specific populations and allow for a quantification of the aligned sample in the space-fixed reference frame. [ABSTRACT FROM AUTHOR]

Using the density functional theory, we conducted a study on the electrification upon contact between hydrophobic liquid molecules and water molecules, revealing localized characteristics of contact-electrification. These "localized features" refer to the specific microscale characteristics where electron transfer predominantly occurs at the contact regions, influenced by factors such as atomic distances and molecular orientations. Although the electrostatic potential and the highest occupied molecular orbital–lowest unoccupied molecular orbital gap offer substantial predictive insights for electron transfer across polymer interfaces, they fall short in capturing the complexities associated with the interaction between hydrophobic liquids and water molecules. The electronegativity of elements at the interface and the localization of molecular orbitals play a decisive role in electron transfer. Simultaneously, for liquid molecules with irregular structures, there is no correlation between the "contact area" and the amount of electron transfer. The "contact area" refers to the surface region where two different liquid molecules come into close proximity. It is defined by the surface area of atoms with interatomic distances smaller than the van der Waals radius. This study challenges traditional assumptions about contact-electrification, particularly in liquid–liquid interfaces, providing new insights into the localized nature of this phenomenon. [ABSTRACT FROM AUTHOR]

The demand for applications, such as coatings, separation filters, and electronic packaging, has greatly driven the research of polymer films. At nanometer scale, mechanical properties of thin polymer films can significantly deviate from bulk. Despite outstanding progresses, there still lack deep discussions on nonlinear viscoelastic–viscoplastic response and their interactions under nanoconfinement. In this work, by conducting measurements via the bubble inflation method and modelling using Schapery and Perzyna equations, we demonstrate nonlinear viscoelastic–viscoplastic properties of freely standing thin polystyrene (PS) films. The results show the unchanged glassy compliance and the rubbery stiffening phenomenon for thin PS films, where the lower rubbery plateau in rubbery stiffening may originate from the induced molecular orientation by plastic deformation. With decreasing film thickness, viscosity and yield stress in viscoplasticity increase in an exponential and a linear trend, respectively, indicating the significant role of nanoconfinement effect on viscoplastic properties. These findings may reveal that there are many properties from linear viscoelasticity to nonlinear viscoelasticity–viscoplasticity that need to be explored and unveiled for sufficient understanding of the nanoconfinement effect on altering mechanical behavior of polymers. [ABSTRACT FROM AUTHOR]

Photoelectron angular distributions (PADs) produced from the photoionization of chiral molecules using elliptically polarized light exhibit a forward/backward asymmetry with respect to the optical propagation direction. By recording these distributions using the velocity-map imaging (VMI) technique, the resulting photoelectron elliptical dichroism (PEELD) has previously been demonstrated as a promising spectroscopic tool for studying chiral molecules in the gas phase. The use of elliptically polarized laser pulses, however, produces PADs (and consequently, PEELD distributions) that do not exhibit cylindrical symmetry about the propagation axis. This leads to significant limitations and challenges when employing conventional VMI acquisition and data processing strategies. Using novel photoelectron image analysis methods based around Hankel transform reconstruction tomography and machine learning, however, we have quantified—for the first time—significant symmetry-breaking contributions to PEELD signals that are of a comparable magnitude to the symmetric terms in the multiphoton ionization of (1R,4R)-(+)- and (1S,4S)-(−)-camphor. This contradicts any assumptions that symmetry-breaking can be ignored when reconstructing VMI data. Furthermore, these same symmetry-breaking terms are expected to appear in any experiment where circular and linear laser fields are used together. This ionization scheme is particularly relevant for investigating dynamics in chiral molecules, but it is not limited to them. Developing a full understanding of these terms and the role they play in the photoionization of chiral molecules is of clear importance if the potential of PEELD and related effects for future practical applications is to be fully realized. [ABSTRACT FROM AUTHOR]

Physical vapor deposition (PVD) provides a route to prepare highly stable and anisotropic organic glasses that are utilized in multi-layer structures such as organic light-emitting devices. While previous work has demonstrated that anisotropic glasses with uniaxial symmetry can be prepared by PVD, here, we prepare biaxially aligned glasses in which molecular orientation has a preferred in-plane direction. With the collective effect of the surface equilibration mechanism and template growth on an aligned substrate, macroscopic biaxial alignment is achieved in depositions as much as 180 K below the clearing point TLC−iso (and 50 K below the glass transition temperature Tg) with single-component disk-like (phenanthroperylene ester) and rod-like (itraconazole) mesogens. The preparation of biaxially aligned organic semiconductors adds a new dimension of structural control for vapor-deposited glasses and may enable polarized emission and in-plane control of charge mobility. [ABSTRACT FROM AUTHOR]

Second-order nonlinear spectroscopy is becoming an increasingly important technique in the study of interfacial systems owing to its marked ability to study molecular structures and interactions. The properties of such a system under investigation are contained within their intrinsic second-order susceptibilities which are mapped onto the measured nonlinear signals (e.g. sum-frequency generation) through the applied experimental settings. Despite this yielding a plethora of information, many crucial aspects of molecular systems typically remain elusive, for example the depth distributions, molecular orientation and local dielectric properties of its constituent chromophores. Here, it is shown that this information is contained within the phase of the measured signal and, critically, can be extracted through measurement of multiple nonlinear pathways (both the sum-frequency and difference-frequency output signals). Furthermore, it is shown that this novel information can directly be correlated to the characteristic vibrational spectra, enabling a new type of advanced sample characterization and a profound analysis of interfacial molecular structures. The theory underlying the different contributions to the measured phase of distinct nonlinear pathways is derived, after which the presented phase disentanglement methodology is experimentally demonstrated for model systems of self-assembled monolayers on several metallic substrates. The obtained phases of the local fields are compared to the corresponding phases of the nonlinear Fresnel factors calculated through the commonly used theoretical model, the three-layer model. It is found that, despite its rather crude assumptions, the model yields remarkable similarity to the experimentally obtained values, thus providing validation of the model for many sample classes. [ABSTRACT FROM AUTHOR]

Phosphonic acid (PA) self‐assembled molecules have recently emerged as efficient hole‐extraction layers (HELs) for organic solar cells (OSCs). However, the structural effects of PAs on their self‐assembly behaviors on indium tin oxide (ITO) and thus photovoltaic performance remain obscure. Herein, we present a novel class of PAs, namely "non‐fused ring dipodal phosphonic acids" (NFR‐DPAs), featuring simple and malleable non‐fused ring backbones and dipodal phosphonic acid anchoring groups. The efficacy of configurational isomerism in modulating the photoelectronic properties and switching molecular orientation of PAs atop electrodes results in distinct substrate surface energy and electronic characteristics. The NFR‐DPA with linear (C2h symmetry) and brominated backbone exhibits favorable face‐on orientation and enhanced work function modification capability compared to its angular (C2v symmetry) and non‐brominated counterparts. This makes it versatile HELs in mitigating interfacial resistance for energy barrier‐free hole collection, and affording optimal active layer morphology, which results in an impressive efficiency of 19.11 % with a low voltage loss of 0.52 V for binary OSC devices and an excellent efficiency of 19.66 % for ternary OSC devices. This study presents a new dimension to design PA‐based HELs for high‐performance OSCs. [ABSTRACT FROM AUTHOR]

Zirconium cobalt alloy (ZrCo) is a promising candidate for tritium storage in fusion reactor, but the surface poisoning caused by trace impurities greatly limits its application. In this work, the interaction mechanisms between nitrogen and ZrCo surface are theoretically explored at the atomic level for the first time. Specifically, the surface exhibits a strong affinity for N atoms with an adsorption energy around −2.0 eV, indicating N can block hydrogenation active sites on ZrCo surface. Seven distinct molecularly adsorbed states have been identified, with their adsorption energies varying from −0.15 to −1.37 eV, depending on both the adsorption site and molecular orientation. The electronic structures and charge distributions indicate that the electrons transfer from ZrCo surface to the anti-bonding orbitals of N 2 , which becomes readily activated with an elongation bond length. Meanwhile, the good mobility of N 2 adsorbate facilitates its dissociation occurring on the specific sites with the energy barriers below 0.3 eV and highly exothermic reaction energies around −3.0 eV, making its dissociative adsorption both kinetically and thermodynamically favorable. Moreover, the high coverage of nitrogen on ZrCo surface significantly restricts hydrogen adsorption and dissociation. Therefore, our results can provide insight into understanding nitrogen poisoning effect on ZrCo surface. • The ZrCo surface exhibits a more affinity for N atoms than H atoms. • The adsorption energy of N 2 is dependent on surface site and molecular orientation. • The good mobility of N 2 adsorbate facilitates its dissociation on the specific sites. • The high coverage of nitrogen significantly restricts hydrogen adsorption and dissociation. [ABSTRACT FROM AUTHOR]

All‐perovskite tandem solar cells (TSCs) are gaining increasing attention due to their potential to surpass the efficiency limit of single‐junction solar cells. However, as the bottom low‐bandgap subcells, tin‐lead (Sn‐Pb) perovskites suffer from severe nonradiative recombination at the interfaces due to their susceptibility to oxidation and poor crystalline morphology. Here a surface modifier 4‐(trifluoromethyl)benzhydrazide (TFH) is reported to construct a reductive chemical environment on the surface of perovskite films and protect them from water and oxygen erosion. TFH anchors onto the Sn‐Pb perovskites in a preferred vertical orientation through dual‐site binding, forming interface dipoles that facilitate charge extraction. The reductive hydrazine groups of TFH can effectively inhibit the oxidation of Sn2+ and I−, thereby reducing the defect density and energy disorder of Sn─Pb perovskites. Consequently, the TFH‐treated devices achieved a champion PCE of 22.88%, maintaining over 93% of the initial efficiency after continuous one‐sun illumination for 500 h. Combined with a 1.79 eV wide‐bandgap subcell, it has demonstrated a PCE of 28.17% in all‐perovskite TSCs. [ABSTRACT FROM AUTHOR]

The emergence of macroscopic self‐propelled oscillatory motion based on molecular design has attracted continual attention in relation to autonomous systems in living organisms. Herein, a series of perylenediimides (PDIs) with various imide side chains was prepared to explore the impact of molecular design and alignment on the self‐propelled motion at the air‐water interface. When placed on an aqueous solution containing a reductant, a solid disk of neutral PDI was reduced to form the water‐soluble, surface‐active PDI dianion species, which induces a surface tension gradient in the vicinity of the disk for self‐propelled motion. We found that centimeter‐scale oscillatory motion could be elicited by controlling the supply rate of PDI dianion species through the reductant concentration and the structure of the imide side chains. Furthermore, we found that the onset and speed of the self‐propelled motion could be changed by the crystallinity of PDI at the water surface. This design principle using π‐conjugated molecules and their self‐assemblies could advance self‐propelled, non‐equilibrium systems powered by chemical energy. [ABSTRACT FROM AUTHOR]

We elucidate a previously unknown synthesis pathway that leads to polymeric nanospheres, orientation-controlled microgels, or microspheroids via single-step polymerization of divinylbenzene (DVB) using initiated chemical vapor deposition (iCVD) in liquid crystals (LC). iCVD supplies vapor-phase reactants continuously, avoiding the critical limitation of reactant-induced disruption of LC structure that has plagued past LC-templated polymerization processes. LC is leveraged as a real-time display of the polymerization conditions and particle emergence, captured using an in situ long-focal range microscope. Detailed image analysis unravels key LC-guided mechanisms during polymerization. pDVB forms nanospheres due to poor solubilization by nematic LC. The nanospheres partition to the LC-solid interface and further assemble into microgel clusters whose orientation is guided by the LC molecular alignment. On further polymerization, microgel clusters transition to microspheroids that resemble liquid drops. We identify key energetic factors that guide trajectories along the synthesis pathway, providing the fundamental basis of a framework for engineering particle synthesis with shape control. [ABSTRACT FROM AUTHOR]

The interaction properties can be significantly improved by using conjugated polymers with aromatic rings for carbon nanotube (CNT)‐reinforced composites. In this study, we investigated the influence of the molecular structure of the polyimide (PI) conjugated polymer on the mechanical properties and interfacial characteristics of CNT/PI composites. To that end, nanocomposites composed of aligned multi‐walled carbon nanotubes (MWNTs) and PI with three different molecular structures were examined. Tensile tests, small‐angle x‐ray scattering (SAXS), and molecular dynamics (MD) simulations were conducted, which revealed significant variations in the tensile properties among the three aligned MWNT/PI nanocomposites. The SAXS analyses indicated that MWNT/BPDA‐PDA had the largest interfacial specific surface area, as corroborated by the MD simulation results, which further demonstrated that the rigidity of the molecular structure influenced the extent of wrapping the PI chains around MWNTs. A highly rigid molecular chain hindered the intrachain folding of the PI chain, facilitating better wrapping of the MWNTs and a larger interfacial area. The MWNTs induced conformational changes in the PI chain owing to π–π stacking. Hermans orientation factor revealed that BPDA‐PDA exhibited the highest degree of orientation with MWNTs, whereas BTDA‐MPD displayed the greatest extent of MWNT‐induced conformational changes. The calculated interaction energy confirmed that MWNT/BTDA‐MPD exhibited the strongest interface strength (−41.50 Kcal/mol/nm2), which was 36.32% and 43.03% higher than that of MWNT/BPDA‐ODA and MWNT/BPDA‐PDA, demonstrating its superior tensile properties. This study provides insights into the interfacial characteristics between conjugated polymers and CNTs, which are essential for designing interfaces and developing high‐performance nanocomposites. Highlights: Interfacial interaction between polyimide and aligned carbon nanotubes was investigated.Modulation by polyimide structures on the mechanical property of composite was revealed.The rigidity of the polyimide hinders the folding and facilitates the wrapping.The interfacial interaction induces molecular orientation in polyimide can be observed by molecular dynamic simulation. [ABSTRACT FROM AUTHOR]

The interfacial compatibility between inorganic particles and polymer is crucial for ensuring high performance of composites. Current efforts to improve interfacial compatibility preferentially rely on organic modification of inorganic particles, leading to their complex process, high costs, and short lifespans due to aging and decomposition of organic modifiers. However, the fabrication of inorganic particles free from organic modification that is highly compatible in polymer still remains a great challenge. Herein, a novel facet‐engineered inorganic particle that exhibit high compatibility with widely used polymer interface without organic modification is reported. Theoretical calculations and experimental results show that (020) and (102) facets of inorganic particles modulate local coordination environment of Ca atoms, which in turn regulate d‐orbital electron density of Ca atoms and electron transfer paths at interfaces between polymer and inorganic particles. This difference alters the molecular diffusion, orientation of molecular chains on surface of inorganic particles, further modulating interfacial compatibility of composites. Surprisingly, the facet‐engineered inorganic particles show exceptional mechanical properties, especially for tensile strain at break, which increases by 395%, far superior to state‐of‐the‐art composites counterparts. Thus, the method can offer a more benign approach to the general production of high‐performance and low‐cost polymer‐inorganic composites for diverse potential applications. [ABSTRACT FROM AUTHOR]

The discovery and measurements of symmetric normal Archimedean spirals from atomic ionization by a pair of time-delayed broadband oppositely circularly polarized pulses revealed their potential of discerning orbital symmetry in atoms. Transferring this tool to molecules substantially increases experimental and theoretical challenges. Here, we show how Einstein's photoelectric effect bypasses the congestion of electronic intermediate states and can access the orbital symmetry in heteronuclear, multi-orbital aligned molecules. Thanks to the broad bandwidth, multi-orbital ionization leads to multiplexed molecular-frame photoelectron momentum distributions, hiding thus any molecular orbital information. Only when molecular orientation is used to manipulate the ionization channels that one can identify a robust doorway into the molecular quantum world in which the asymmetry inherent to the highest-occupied molecular orbital can be unambiguously revealed by the asymmetric molecular spirals from single-color pulses. Our results demonstrate the potential of polarization-tailored attopulse sequences for the retrieval of spectroscopic details on molecular orbital symmetries. For pulse bandwidth larger than the energy gap between molecular orbitals, distinguishing contributions of electrons photoionized from different orbitals is a major hurdle. Here, the authors mitigate this issue by rotating light with respect to the molecular axis and show that asymmetric spirals are a new source of information for molecular orbital symmetries. [ABSTRACT FROM AUTHOR]

Material‐networked conduction paths provide nonlinear electronic properties, which are essential components of computing and physically mimic the brain. In this study, the formation of conjugated polymer monolayer networks and their nonlinear charge transport is demonstrated. Poly(3‐hexylthiophene) (P3HT) monolayer networks doped with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) is fabricated using the co‐spread method with an amphiphilic liquid crystal molecule at the air–water interface. Atomic force microscopy and Ultraviolet–visible–near‐infrared absorption spectroscopy measurements reveal the network surface morphologies and doped electronic states. The correlation between the nonlinear electronic characteristics and network structures of the P3HT/F4TCNQ monolayer networks is further systematically investigated through current–voltage and voltage–time measurements for various doping levels, network densities, and numbers of transferred layers. The current–voltage characteristics of the P3HT/F4TCNQ monolayer network device with a simple two‐terminal structure exhibit nonlinear and ohmic conduction behavior, which depend strongly on the network density and geometric dimension (number of transferred layers). It is concluded that the nonlinear properties arise from the limited and unique network of 2D conduction passes. This study highlights the unique features of conducting polymer monolayer networks, paving the way for neuromorphic device applications including conjugated semiconducting polymer‐based material reservoirs with controllable nanostructures. [ABSTRACT FROM AUTHOR]

The molecular arrangement of the extremely uniaxial thin film was determined using X-ray analysis, including grazing incidence wide-angle X-ray scattering. The highly oriented film was obtained by depositing a bisazo dye onto an aligned polytetrafluoroethylene (PTFE) layer via vacuum evaporation, as shown previously. The X-ray analysis indicated that the molecules are arranged in parallel or antiparallel orientations within the unit cell. Moreover, their long axes are parallel to each other within the grains which are uniformly oriented throughout the film. These results confirm the driving force of the orientation reported previously using a molecular dynamics model: dye molecules trapped along the atomic grooves between adjacent PTFE chains serve as nuclei for crystal growth. In addition, the long molecular axes remain parallel to the rubbing direction, although some grains are inclined in the short-axis direction. This molecular arrangement in the film could contribute to a high degree of uniaxial orientation. [ABSTRACT FROM AUTHOR]

Ab initio MD studies have been performed on stacked adenine–thymine (A–T) and guanine–cytosine (G–C) nucleobase pairs solvated in water using Born–Oppenheimer molecular dynamics. These two systems have been analyzed using RDF, SDF, angle–distance CDF (combined distribution functions), plane projection analysis, hydrogen bond analysis, and non–covalent interaction (NCI) plots. The stacking property studies have shown that the molecular orientation of the A–T pair is completely opposite to that of the G–C pair though the center of mass distance between the two molecules is similar. The G–C pair shows significantly more stability in water than the A–T system does. RDF analyses show that the –NH– group and carbonyl groups show predominant interaction with water molecules. Water molecules are found to be most in numbers around the cytosine molecule and least around the adenine molecule. Hydrogen bonding studies show that the guanine molecule forms the highest number of hydrogen bonds with water molecules. On the other hand, the hydrogen atom attached to the –NH– group of adenine molecule shows the longest mean H–bond lifetime with water oxygen atoms. NCI interactions calculated through the ab initio method help us to visualize the π-electron stacking and H–bonding between aromatic nucleobases and water molecules. A great shift in bond polarity and interaction intensity in different functional groups is observed for the nucleobases going from individually solvated molecules to paired states. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs), owing to their superior electrical and mechanical properties, are a promising alternative to nonmetallic electrically conducting materials. In practice, cellulose as a low‐cost sustainable matrix has been used to prepare the aqueous dispersion of cellulose‐CNT (C‐CNT) nanocomposites. However, the compatibility with conventional solution‐processing and structural rearrangement for improving conductivity has yet to be determined. Herein, a straightforward route to prepare a conductive composite material from single‐walled CNTs (SWCNTs) and natural pulp is reported. High‐power shaking realizes the self‐alignment of individual SWCNTs in a cellulose matrix, resulting from the structural change in molecular orientations owing to countless collisions of zirconia beads in the aqueous mixture. The structural analysis of the dried C‐CNT films confirms that the entanglement and dispersion of C‐CNT nanowires determine the mechanical and electrical properties. Moreover, the rheological behavior of C‐CNT inks explains their coating and printing characteristics. By controlling shaking time, the electrical conductivity of the C‐CNT films with only 9 wt.% of SWCNTs from 0.9 to 102.4 S cm−1 are adjusted. the optimized C‐CNT ink is highly compatible with the conventional coating and printing processes on diverse substrates, thus finding potential applications in eco‐friendly, highly flexible, and stretchable electrodes is also demonstrated. [ABSTRACT FROM AUTHOR]

Interfacial defects between perovskite and adjacent charge transport layers present a significant obstacle, hindering the enhancement of power conversion efficiency (PCE) and stability in perovskite solar cells (PSCs). To address this challenge, a dual‐interface modification is proposed to aim at improving the performance of mixed‐halide PSCs. Specifically, the hole‐collecting side is modified with 5‐Aminopyridine‐2‐carboxylic Acid (APC), while the electron‐collecting side is modified with 2‐thiopheneethylammonium chloride (TEACl). The multifunctional APC enhances charge transfer by tailoring the interface between the perovskite and poly(triarylamine) (PTAA) through multiple bonding interactions, thereby suppressing interfacial nonradiative recombination. Density functional theory studies reveal that APC on the perovskite surface induces uniform adsorption energy, promoting homogenous crystallization without residual stress. Additionally, APC interlayer eliminates the localized edge states induced by the iodine vacancies near the conduction band edge. Further improvement in the device performance is achieved by passivating the top perovskite surface with TEACl, leading to well‐matched energy bands and reduced vacancy trap states. As a result, champion cell achieves a PCE of 24.87% with an open‐circuit voltage of 1.188 V. Furthermore, The dual‐interface modification improves thermal stability due to enhanced ion‐migration activation energy. [ABSTRACT FROM AUTHOR]

Lithography technology is a powerful tool for preparing complex microstructures through projecting patterns from static templates with permanent features onto samples. To simplify fabrication and alignment processes, dynamic photomask for multiple configurations preparation becomes increasingly noteworthy. Hereby, we report a dynamic photomask by assembling the electrically stimulated nematic liquid crystal (NLC) into multifarious architectures. This results in reconfigurable and switchable diffraction patterns due to the hybrid phase arising from the NLC molecular orientations. These diffraction patterns are adopted as metamask to produce multiple microstructures with height gradients in one-step exposure and hierarchical microstructures through multiple in-situ exposures using standard photolithography. The fabricated pattern has feature size about 3.2 times smaller than the electrode pattern and can be transferred onto silicon wafer. This strategy can be extended to design diverse microstructures with great flexibility and controllability, offers a promising avenue for fabricating metamaterials via complex structures with simplified lithography processes. Lithography technology enables the creation of intricate microstructures by projecting patterns from fixed templates onto samples. Liu et al. report a dynamic photomask using electrically stimulated nematic liquid crystals, which provides reconfigurable diffraction patterns, simplifying microstructure fabrication with enhanced flexibility and precision. [ABSTRACT FROM AUTHOR]

Polar organic molecules form spontaneous polarization in vacuum-deposited films by permanent dipole orientations in the films, originating from the molecule's potential ability to align itself on the film surface during deposition. This study focuses on developing polar molecules that exhibit spontaneous orientation polarization (SOP) and possess a high surface potential. In the proposed molecular design, a hexafluoropropane (6F) unit facilitates spontaneous molecular orientation to align the permanent dipoles, and a phthalimide unit induces strong molecular polarization. Furthermore, the introduction of phthalimides into the molecular backbone raises the glass transition temperature of the molecules, leading to the suppression of molecular mobility on the film surface during film deposition and an improvement in the dipole orientation. The resulting surface potential slope is approximately 280 mV nm−1 without substrate temperature control. Furthermore, this work proposes a method using position isomers as a design strategy to tune the SOP polarity. The substitution position of the strong polar units influences the direction of the total molecular dipoles and affects the SOP polarity of the 6F-based molecules. The proposed molecular designs in this study provide wide tunability of the SOP intensity and polarity, which contributes to highly efficient organic optoelectronic and energy-harvesting devices. Polar organic molecules form spontaneous polarization in vacuum-deposited films originating from the molecule's potential ability to align itself on the film surface during deposition. Here, the author incorporates fluoroalkyl and phthalimide units to the molecular backbone to improve spontaneous molecular orientation facilitating strong polarization in vacuum deposited films. [ABSTRACT FROM AUTHOR]

The singlet fission characteristics of aqueous nanoparticles, self‐assembled from ion pairs of tetracene dicarboxylic acid and various amines with or without chirality, are thoroughly investigated. The structure of the ammonium molecule, the counterion, is found to play a decisive role in determining the molecular orientation of the ion pairs and its regularity, spectroscopic properties, the strength of the intermolecular coupling between the tetracene chromophores, and the consequent singlet fission process. Using chiral amines has led to the formation of crystalline nanosheets and efficient singlet fission with a triplet quantum yield as high as 133% ±20% and a rate constant of 6.99 × 109 s−1. The chiral ion pairs also provide a separation channel to free triplets with yields as high as 33% ±10%. In contrast, nanoparticles with achiral counterions do not show singlet fission, which gave low or high fluorescence quantum yields depending on the size of the counterions. The racemic ion pair produces a correlated triplet pair intermediate by singlet fission, but no decorrelation into two free triplets is observed, as triplet‐triplet annihilation dominates. The introduction of chirality enables higher control over orientation and singlet fission in self‐assembled chromophores. It provides new design guidelines for singlet fission materials. [ABSTRACT FROM AUTHOR]

Nanostructured polymer-dispersed liquid crystals (nano-PDLCs) are transparent and optically isotropic materials in which submicron-sized liquid crystal (LC) domains are dispersed within a polymer matrix. Nano-PDLCs can induce birefringence by applying an electric field (E-field) based on the reorientation of the LC molecules. If nano-PDLCs are utilized as light-scattering-less birefringence memory materials, it is necessary to suppress the relaxation of the LC molecule orientation after the removal of the E-field. We focused on the ferroelectric smectic A (SmA) phase to suppress the relaxation of LC molecules, owing to its layered structure and high viscosity. Although nano-PDLCs require a strong E-field to reorient their LC molecules because of the anchoring effect at the LC/polymer interface, the required field strength can be reduced using a ferroelectric smectic A (SmAF) LC with a large dielectric constant. In this study, we fabricated a nano-PDLC by shining an ultraviolet light on a mixture comprised an SmAF LC, photocurable monomers, and a photo-initiator. The electro-birefringence effect was evaluated using polarizing optical microscopy. After the removal of the E-field, an enhanced memory effect was observed in the sample using SmAF LC compared with nematic LC-based nano-PDLCs. [ABSTRACT FROM AUTHOR]

Actuators based on shape memory polymers and composites incorporating nanomaterial additives have been extensively studied; achieving both high output stress and precise shape change by low‐cost, scalable methods is a long‐term‐desired yet challenging task. Here, conventional polymers (polyurea) and carbon nanotube (CNT) fillers are combined to fabricate reinforced composite fibers with exceptional actuation performance, by a wet‐spinning method amenable for continuous production. It is found that a thermal‐induced shrinkage step could obtain densified strong fibers, and the presence of CNTs effectively promotes the tensile orientation of polymer molecular chains, leading to much improved mechanical properties. Consequently, the CNT/ polyurea composite fibers exhibit stresses as high as 33 MPa within 0.36 s during thermal actuation, and stresses up to 22 MPa upon electrical stimulation enabled by the built‐in conductive CNT networks. Utilizing the flexible thin fibers, various shape change behavior are also demonstrated including the conversion between different structures/curvatures, and recovery of predefined simple patterns. This high‐performance composite fibers, capable of both thermal and electrical actuation and produced by low‐cost materials and fabrication process, may find many potential applications in wearable devices, robotics, and biomedical areas. [ABSTRACT FROM AUTHOR]

Three novel asymmetric Ir(III) complexes have been rationally designed to optimize their emitting dipole orientations (EDO) and enhance light outcoupling in blue phosphorescent organic light‐emitting diodes (OLEDs), thereby boosting their external quantum efficiency (EQE). Bulky electron‐donating groups (EDGs), namely: carbazole (Cz), di‐tert‐butyl carbazole (tBuCz), and phenoxazine (Pxz) are incorporated into the tridentate dicarbene pincer chelate to induce high degree of packing anisotropy, simultaneously enhancing their photophysical properties. Angle‐dependent photoluminescence (ADPL) measurements indicate increased horizontal transition dipole ratios of 0.89 and 0.90 for the Ir(III) complexes Cz‐dfppy‐CN and tBuCz‐dfppy‐CN, respectively. Analysis of the single crystal structure and density functional theory (DFT) calculation results revealed an inherent correlation between molecular aspect ratio and EDO. Utilizing the newly obtained emitters, the blue OLED devices demonstrated exceptional performance, achieving a maximum EQE of 30.7% at a Commission International de l'Eclairage (CIE) coordinate of (0.140, 0.148). Optical transfer matrix‐based simulations confirmed a maximum outcoupling efficiency of 35% due to improved EDO. Finally, the tandem OLED and hyper‐OLED devices exhibited a maximum EQE of 44.2% and 31.6%, respectively, together with good device stability. This rational molecular design provides straightforward guidelines to reach highly efficient and stable saturated blue emission. [ABSTRACT FROM AUTHOR]

Spontaneous alignment of molecular electric dipole moments, known as spontaneous orientation polarization (SOP), is present in many organic electronic materials. The SOP‐induced field changes the internal voltage distribution within the device, altering polaron injection and accumulation. The important role of SOP in organic light‐emitting devices (OLEDs) has recently been emphasized with clear links between dipole alignment and device efficiency and operational lifetime. Prior work has thus sought to engineer SOP via changes in thin film composition or processing conditions. These efforts have generally been directed at the OLED electron transport layer, which can show strong SOP. This work takes a different approach, focusing instead on how changes in device architecture can be applied to tune the magnitude and dynamics of polaron accumulation in response to SOP. In this work, it is demonstrated that the introduction of SOP into the device emissive layer offers control over the spatial location of accumulation. In parallel, insertion of a spacer layer between the hole transport and emissive layers can be used to tune the polaron accumulation rate and density during device operation. Both of these architectural changes permit an increase in OLED efficiency and a pathway around the deleterious impact of SOP‐induced polaron accumulation. [ABSTRACT FROM AUTHOR]

The understanding of the optical characteristics and the influence of thermally induced crystallization is vital to evaluate newly synthesized organic semiconductors for their potential applications. Variable‐angle spectroscopic ellipsometry (VASE) is employed to determine the complex dielectric function of two recently developed discrete oligomers based on naphthalene diimide (NDI) and bithiophene (T2), applying an anisotropic optical model. It is shown that the as‐cast films are optically near‐isotropic, while the annealed films exhibit pronounced anisotropies with respect to the orientation of the π−π* transition. Differences between the two distinct molecules are observed and discussed. The degree of optical anisotropy is quantified using the average molecular orientation angle φ, associated with the orientation of the π−π* transition dipole, and the related orientation order parameter S. The molecules are shown to form crystallites of several microns in size upon annealing. Imaging ellipsometry is thus additionally employed to study their optical anisotropy on a microscopic scale, and the agreement with results from macroscopic measurements is evaluated. [ABSTRACT FROM AUTHOR]

Understanding the effects of phenomena occurring at electrically charged interfaces, such as charge inversion (CI), is crucial for enabling electroosmosis as an efficient transport mechanism in nanodevices. Here, we employ molecular dynamics (MD) simulations to systematically analyze the effect of CI on the electrokinetic transport of multivalent ionic solutions confined in amorphous silica nanochannels. We employ mixtures of monovalent and multivalent counterions while fixing the total ionic concentration to establish correlations between observed phenomena and the amount of multivalent ionic species in the electrolyte solution. The results show that the development of CI is related to a decrease in the mobility of the fluid layers adjacent to the charged surface. In addition, we observe that interfacial overcharging disrupts the water molecular orientation in the fluid layers adjacent to the channel walls. From the non-equilibrium MD simulations of electro-osmotic flow, we disclose the influence of phenomena related to the presence of CI. In particular, flow reversal occurs in scenarios involving CI due to increased local viscosity and a higher concentration of coions within the hydrodynamically mobile and electrokinetically active region of the charged interface. We also find that the magnitude of the wall zeta (ζ) potential displays a monotonic increase with the development of CI in the system. Moreover, we explain why positioning the wall ζ potential at an imaginary (slip) plane, which separates the hydrodynamically mobile and immobile fluid, is misleading. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of pre-gelation on cellulose dissolved in LiCl/DMAc solutions to enhance the properties of regenerated cellulose materials. This study focuses on characterizing the crystallinity, molecular orientation, and mechanical performance of cellulose fibers and hydrogels prepared with and without pre-gelation treatment. X-ray diffraction (XRD) analysis reveals that crystallinity improvement from 55% in untreated fibers to 59% in fibers pre-gelled for 3 and 7 days, indicating a more ordered arrangement of cellulose chains post-regeneration. Additionally, XRD patterns show improved chain alignment in pre-gelled fibers, as indicated by reduced full width at half the maximum of Azimuthal scans. Mechanical testing demonstrates a 30% increase in tensile strength and a doubling of the compression modulus for pre-gelled fibers compared to untreated fibers. These findings underscore the role of pre-gelation in optimizing cellulose material properties for applications ranging from advanced textiles to biomaterials and sustainable packaging. Future research directions include further exploration of the structural and functional benefits of pre-gelation in cellulose processing and its broader implications in material science and engineering. [ABSTRACT FROM AUTHOR]

In this paper, we consider the partial regularity of suitable weak solution to the 3D simplify Ericksen–Leslie system modeling the hydrodynamical motion of nematic liquid crystal flow, which is a coupled system with the Navier–Stokes equations for the velocity field and kinematic transport equations for the molecular orientation field. We present a new regularity criteria for suitable weak solutions to the 3D simplified Ericksen–Leslie system. Moreover, under the condition ∥u∥Ltp,∞Lxq([−1,0]×R3)+∥∇d∥Ltp,∞Lxq([−1,0]×R3):=K<∞,with2p+3q=1and3

Poly(butylene succinate) (PBS) was melt-blended with paramylon based mixed ester, paramylon propionate hexanoate (PaPrHe) and characterized for its morphology, thermal and mechanical properties. The PBS/PaPrHe blends were found to be immiscible throughout the loading range of PaPrHe (10–90 wt%), with individual glass transition peaks. Due to the immiscibility, there was phase separation observed in the bulk, evident by sea-island morphology. However, further observation of the micro-structure revealed that, in low PaPrHe loading (10–30 wt%), there was a micron to sub-micron order distribution of PBS particles and partially miscible PBS/PaPrHe phase. On increasing the PaPrHe to 50 wt% and beyond, the sub-micron scale domains fused to form a co-continuous morphology. As a result, the impact strength of PBS increased from 6.6 to 16.4 kJ/m2 in the 50/50 blend. Under tensile loading, the strength at break and elongation decreased after the introduction of less-flexible PaPrHe particles in the blend. This could be countered by uniaxially stretching the blended films with 10–30 wt% PaPrHe, after which the tensile strength increased by up to 380% (from 33–52 MPa to 165–200 MPa) compared to the unstretched films, attributable to the increased degree of orientation of the molecular chains. In terms of thermal processability, all the blend ratios had high thermal degradation temperature (>350 °C), higher than the melt-flow temperature (124–133 °C) providing a wide processing window. Overall, PBS/PaPrHe blend is a novel bio-based blend with properties suitable for packaging, mulching, and related applications. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The structural revolutions of non‐fullerene acceptors (NFAs) have driven continuous efficiency breakthroughs in organic solar cells (OSCs). Rational regulation of NFA structures toward efficient exciton dissociation and mitigated non‐radiative recombination is pivotal for OSCs. The incorporation of asymmetric side chains on NFAs can often achieve these goals by inducing a desirable aggregate state. However, it lacks the studies to directly correlate the side‐chain symmetry of NFAs with the exciton delocalization and triplet dynamics in OSCs. Herein, The influence of structural symmetry on the aggregate properties is systematically investigated and exciton/charge dynamics based on two developed biaxial‐conjugated NFAs with varied side‐chain symmetry. The symmetric NFA having diverse molecular packing orientations can form multiple charge transfer channels in its blend with polymer donor, which cannot be found in that comprising the asymmetric ones. Moreover, a slower rate and lower ratio of the spin‐triplet state are formed in the blend of symmetric NFA, resulting in a much lower non‐radiative voltage loss in corresponding OSCs. This study reveals the distinct advantages of symmetric NFAs in both aggregate properties and exciton/charge dynamics over those of asymmetric ones, paving the way for developing high‐performance OSCs using easier‐to‐prepare, low‐cost symmetric materials. [ABSTRACT FROM AUTHOR]

Manipulating the conjugated backbone of small molecule acceptors (SMAs) is of particular importance in developing efficient organic solar cells (OSCs). Recently, trimers and other multi-arm SMAs have been found to be able to provide more intermolecular interaction, demonstrating excellent molecular stacking and device performance. However, the synthesis of this type of SMA usually relies on tristin or polystin compounds. Instead, expanding multiple arms in the central cores of SMAs is relatively simple and not restricted by tin compounds. Based on the quinoxaline core, two kinds of multi-arm SMAs, FQx-IC and TQx-IC with 4 and 3 arms, have been developed in this work. Compared to FQx-IC, TQx-IC exhibits an ordered face-on molecular orientation, appropriate film-forming process, and more favorable phase separation morphology and balanced charge transport. When blended with the polymer donor D18, OSCs based on TQx-IC achieve a power conversion efficiency (PCE) of 17.36%, which is superior to the device based on D18:FQx-IC (16.24%). In addition, using the ternary strategy of incorporating the TQx-IC into the D18:Y6 system, an excellent PCE of 18.82% is achieved. Therefore, this multi-arm molecular design strategy has great potential for regulating molecular stacking, absorption, and the corresponding device performance. [ABSTRACT FROM AUTHOR]

In this paper, electrically responsive liquid crystal network (LCN) based soft actuators are presented that can achieve large deformations under an alternating current (AC) electric field. These LCN actuators are prepared by photopolymerization of liquid crystal acrylate monomers with polar end groups, which form polar side chains in the networks. Actuation is initiated by applying a high‐frequency and low‐voltage electric field. When this AC field is applied, the LC mesogens, especially the polar side chains, can oscillate, decreasing the molecular order, and creating free volume in the LCNs, which further results in anisotropic deformation. The formed shapes range from bending to bulging, depending on the programmed molecular alignment. The actuation proceeds fast within 5 s both for activation and for the relaxation to the initial state upon switching the power on and off. This LCN soft actuator exhibits fast response, low power consumption, and high precision, making it a promising candidate for applications in soft robotics, microfluidics, and biomimetic muscles. [ABSTRACT FROM AUTHOR]

High mechanical strength, toughness, and fatigue resistance are essential to improve the reliability of conductive hydrogels for self‐powered sensing. However, achieving mutually exclusive properties simultaneously remains challenging. Hence, a novel directed interlocking strategy based on topological network structure and mechanical training is proposed to construct tough hydrogels by optimizing the network structure and modulating the orientation of molecular chains. Combining Zn2+ crosslinked cellulose nanofibers (CNFs) and a polyacrylamide‐poly(vinyl alcohol) double‐network, the unique interlocked‐network structure exhibits an enhanced toughening effect due to hydrogen bonding and metal‐ligand interactions. The aligned nanocrystalline domains achieved by training further contribute to an increase in the toughness and fatigue thresholds. This innovative approach synergistically enhances the mechanical properties of the nano‐conductive hydrogel, achieving a maximum tensile strength of 4.98 MPa and a toughness of 48 MJ m−3. Notably, the CNFs template with anchored polyaniline, when oriented through mechanical training, forms a unique directional conductive pathway, which significantly enhances the power output performance. Besides, a motion recognition system based on a self‐powered sensing device is designed with the assistance of deep learning techniques to accurately identify human motion behaviors. This work showcases a potentially transformative flexible electronic material for self‐powered sensing systems and intelligent recognition systems. [ABSTRACT FROM AUTHOR]

In this study, we synthesized four bifunctional compounds containing two alkoxy groups, at which reactive thiol groups were introduced. Among these compounds, a compound with four and five methylene units in each alkyl chain did not exhibit a liquid crystalline phase. The other three compounds exhibit one or two liquid crystalline phases, and the number of liquid crystalline phases depends on the number of methylene units in their alkyl chains. These liquid crystalline compounds were oriented in one direction using a rubbed alignment film, and the oriented compounds were transferred onto a gold substrate. Using these gold substrates as working electrodes, cyclic voltammetry (CV) was performed with potassium ferricyanide as the redox probe. As the deposition time increased, the current intensities of a pair of redox waves gradually decreased. This trend suggests that with longer deposition times, a larger amount of the liquid crystalline compound was transferred to the gold substrate surface. These findings shed light on the relationship among the structures of bifunctional compounds, their liquid crystalline behavior, and their alignment properties on gold substrates, thereby offering valuable insights for potential applications in nanotechnology and materials science. [ABSTRACT FROM AUTHOR]

The study investigated the structures and properties of lyocell composite fibers with acetylated cellulose with varying relative acetylation substitution degrees (RDS). During pretreatment with NaOH/ethanol solution, some acetyl groups in the acetylated cellulose were hydrolyzed, leading to improve solubility in N-methylmorpholine-N-oxide (NMMO). The RDS was utilized to quantify the content of acetyl groups and acetylated cellulose with RDS between 0.516 ~ 0.571 that could dissolve in NMMO completely. The compatibility between cellulose and acetylated cellulose, with RDS values of 0.516, 0.543 and 0.571 respectively, was demonstrated through rheological and contact angle tests. Although the addition of acetylated cellulose did not change the crystalline structure and comprehensive performance of the composite fiber, it mainly disturbed molecular orientation of amorphous region, crystallinity and grain size. Besides the strengthening of hydrogen bonding between the two components, and the transverse connection between the aggregates were enhanced, thus reducing fibrillation. This paper provides a green modification approach that can be scaled up for industrial application, aiming to mitigated fibrillation issues in lyocell fibers. [ABSTRACT FROM AUTHOR]

Highlights For traditional materials, a polymer composite with high performance and large‐scale production is still the goal pursued by researchers. In our work, polyamide 6/calcium sulfate whiskers (PA6/SCW) composites were fabricated via melt‐compouding method. The calcium sulfate whisker based on gypsum mineral was used as reinforcement. After grafting silane coupling agent on the whisker surface, the whiskers showed a significant reinforcing effect in polyamide. The mechanics and tribology performance of the samples had been significantly inhanced. Based on the nucleation mechanism of lattice matching, calcium sulfate whiskers have obvious heterogeneous nucleation effect in PA6 matrix, while the crystallization period was slightly prolonged. This was caused by the network structure formed by the whiskers in the matrix, which impeded the free movement of polymer chain segments. In combination with the orientation degree of the molecular chains measured by the interdigital electrode, the reinforcing effect of the oriented PA6 specimens was derived from the orientation arrangement of the whiskers and the efficient load transfer. Mechanical and tribological properties of composite were significantly improved. The composite could achieved large‐scale production due to simple preparation. The whiskers had obvious heterogeneous nucleation effect in matrix. The reinforcing effect was derived from efficient load transfer from whiskers. [ABSTRACT FROM AUTHOR]

Multidimensional solitons are prevalent in numerous research fields. In orientationally ordered soft matter system, three-dimensional director solitons exemplify the localized distortion of molecular orientation. However, their precise manipulation remains challenging due to unpredictable and uncontrolled generation. Here, we utilize preimposed programmable photopatterning in nematics to control the kinetics of director solitons. This enables both unidirectional and bidirectional generation at specific locations and times, confinement within micron-scaled patterns of diverse shapes, and directed propagation along predefined trajectories. A focused dynamical model provides insight into the origins of these solitons and aligns closely with experimental observations, underscoring the pivotal role of anchoring conditions in soliton manipulation. Our findings pave the way for diverse fundamental research avenues and promising applications, including microcargo transportation and optical information processing. [ABSTRACT FROM AUTHOR]

Size-selected linear sp-carbon chain molecules of hydrogen-capped polyyne C12H2 are dispersed in stretched polyvinyl alcohol (PVA) films to align them along the direction of stretching of the film. The order parameter for anisotropic molecular orientation is determined from the angular dependence of UV absorption band intensities using linearly polarized incident light. Phosphorescence spectra at cryogenic temperature of 20 K of aligned C12H2 polyyne molecules in the stretched PVA film exhibit anisotropic properties, namely linearly polarized luminescence (LPL). Molecular orientation is modeled by the | cos ⁡ θ | N distribution of linear molecules to simulate angle-dependent polarized optical emission intensities. The ensemble of aligned polyyne molecules is demonstrated to be an ideal molecular system for consideration of linear dichroism in LPL as well as in photo absorption. [ABSTRACT FROM AUTHOR]

Nanomaterials are known as the most promising materials of the 21st century, among which nanofibers have become a hot research and development topic in academia and industry due to their high aspect ratio, high specific surface area, high molecular orientation, high crystallinity, excellent mechanical properties, and many other advantages. Electrospinning is the most important preparation method for nanofibers and their thin membranes due to its controllability, versatility, low cost, and simplicity. Adding nanofillers such as ceramics, metals, and carbon materials to the electrospinning polymer solutions to prepare composites can further improve the mechanical strength and multi-functionality of nanofibers and their thin membranes and also provide possibilities for their widespread applications. Based on the rapid development in the field of polymer composite nanofibers, this review focuses on polyurethane (PU)-based composite nanofibers as the main representative and reviews their latest practical applications in many fields such as sound-absorbing materials, biomedical materials (including tissue engineering implants, drug delivery systems, wound dressings and other anti-bacterial materials, health materials, etc.), wearable sensing devices and energy harvesters, adsorbent materials, electromagnetic shielding materials, and reinforcement materials. Finally, a summary of their performance–application relationship and prospects for further development are given. This review is expected to provide some practical experience and theoretical guidance for further developments in related fields. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)