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Many modern anti-icing and anti-fouling coatings rely on soft, low surface energy elastomeric materials such as polydimethylsiloxane for their functionality. While the low surface energy is desirable for reducing adhesion, very little work considers the larger contribution to adhesive failure caused by the viscoelastic nature of elastomers. Here we examine several different siloxane elastomers using a JKR adhesion test, which was operated over a range of different speeds and temperatures. Additionally, we characterize the dynamic mechanical modulus over a large range of frequencies for each material. We note that surface energies of the materials are all similar, but variation in adhesion strength is clear in the data. The variation at low speeds is related to elastomer architecture but the speed dependence itself is independent of architecture. Qualitative correlations are noted between the JKR adhesion measurements and the dynamic moduli. Finally, an attempt is made to directly compare moduli and adhesion through the recent Persson–Brener model. Approximations of the model are shown to be inaccurate. The full model is found to be accurate at low speeds, although it fails to precisely capture higher speed behaviour. [ABSTRACT FROM AUTHOR]

Cutting of soft materials is a complex problem, which is still not well understood at the fundamental level, especially for soft materials. The cutting process we consider is slicing, which starts with indentation, followed by sliding of a knife on the material to be cut. Here, we describe cutting experiments on PDMS elastomers with three different moduli. Our experiments reveal typical stages of this cutting process, starting with indentation and ending at steady state cutting. The process starts with a pre-cutting phase in which the blade does not slip grossly relative to the solid to be cut, and deformation is mostly elastic. Slip of the blade initiates suddenly and is often accompanied by initiation of cutting. Cutting is relatively smooth in the next stage, which requires a continuous increase in shear force. For soft PDMS, this smooth cutting stage is followed by one in which folds or creases form on the cutting surface. The corresponding shear force response is no longer smooth as "steady" sliding occurs in a stick–slip fashion with oscillatory forces. The average shear force reaches a plateau and no longer increases with shear displacement. Experimental observations of the various cutting stages are interpreted quantitatively. [ABSTRACT FROM AUTHOR]

ABSTRACT: Mechanically interlocked polymers (MIPs) are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and translational mechanical movements at the molecular level. However, the investigations on their mechanical properties are lagging far behind their structural fabrication, especially for linear polyrotaxanes in bulk. Herein, we report stretchable poly[2]rotaxane elastomers (PREs) which integrate numerous mechanical bonds in the polymeric backbone to boost macroscopic mechanical properties. Specifically, we have synthesized a hydroxy-functionalized [2]rotaxane that subsequently participates in the condensation polymerization with diisocyanate to form PREs. Benefitting from the peculiar structural and dynamic characteristics of the poly[2]rotaxane, the representative PRE exhibits favorable mechanical performance in terms of stretchability (∼1200%), Young's modulus (24.6 MPa), and toughness (49.5 MJ/m3). Moreover, we present our poly[2]rotaxanes as model systems to understand the relationship between mechanical bonds and macroscopic mechanical properties. It is concluded that the mechanical properties of our PREs are mainly determined by the unique topological architectures which possess a consecutive energy dissipation pathway including the dissociation of host−guest interaction and consequential sliding motion of the wheel along the axle in the [2]rotaxane motif.

When dielectric-elastomer (DE) resonators are operated under large alternating voltage excitations, strong geometric and material nonlinearities can significantly affect the dynamic performance. Based on the virtual work principle, a dynamic model of a circular DE resonator is established in this work. Static analysis is conducted to study the impacts of the control voltage on the strain and natural frequency of the DE resonator at equilibrium. A modified Incremental Harmonic Balance and arc-length methods are used to obtain dynamic responses of the system excited by alternating voltages, and stability analysis is conducted using the Floquet theory. The effects of the mechanical parameters are studied, and period-doubling bifurcations are observed, which are produced by the parametric excitation of the voltage. The bifurcation phenomenon is comprehensively investigated through analysis of the voltage, stress, and damping coefficient, which provides design guidance for DE resonators. [ABSTRACT FROM AUTHOR]

The electrical properties of polymer nanocomposites are governed by the behavior of the internal charges. In particular, the interphase around the nanoparticles strongly influences the distribution and mobility of charge carriers within the nanocomposites, which, in turn, impacts the performance of these materials. In this work, we probe the internal charge behavior in the presence of nanoparticles with a focus on the low-frequency regime using a suite of techniques. By investigating the depolarizing currents and the dependence of the dielectric properties on the frequency and temperature, we demonstrate that the interphases redistribute the space charges, increase their trap depth, and suppress the electrode polarization in an elastomeric nanocomposite. Additionally, we study the effect of the nanoparticle content on the dielectric behavior by comparing the internal charge behavior of 1, 2, and 4 vol. % nanocomposites. At only 4 vol. % loading, the mobility of charge carriers is effectively limited, leading to lower dc conductivity compared to the unfilled elastomer, and 1 and 2 vol. % nanocomposites. These findings are based on the model materials used in this study, TiO2 nanoparticles and polydimethylsiloxane, and can be extended to other nanoparticulate-filled elastomer composites to design lightweight dielectrics, actuators, and sensors with improved capabilities. Judicious manipulation of interfacial phenomena in polymer nanocomposites—especially those with a dilute content of nanoparticles—provides a promising path forward for the design of materials with exceptional electrical and other physical properties. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is a disruptive manufacturing process that gives designers freedom to create highly complex shapes through free-form fabrication. The majority of polymers used in extrusion AM are thermoplastics because they are easy to process in affordable machines. While there are a number of moderate modulus thermoplastics in regular use in AM, thermoplastics are known to weaken with increases in temperature or exposure to solvents and many commodity thermoplastics used in AM are brittle. On the other hand, there are few elastomers, and even fewer elastomer reinforcement schemes, that are accessible using standard AM technologies. In this work, we report a novel dual extrusion process that integrates elastomeric silicone with reinforcing thermoplastic. By developing and demonstrating a dual extrusion 3D printer that can process common thermoplastics with commercially available thermosetting silicones, new types of composite elastomers are reported with good mechanical performance. The 0[degrees]/20[degrees]/-20[degrees] grid pattern thermoplastic reinforced samples achieved 2.5 MPa tensile strength in low extension region (0.5 strain), which improves the initial stiffness of the composite component. Desired mechanical responses of composite structures can be realized by tuning the reinforcement volume ratio and infill percentages, and applying various types of reinforcement mesh patterns and thermoplastics. Highlights * A dual extrusion process integrates fus filament fabrication and direct ink writing technologies. * Thermoplastic reinforced silicone composite with stiff/soft properties. * Tunable volume ratio, infill percentage, mesh pattern, and material option. KEYWORDS material characterization, material extrusion, thermoplastic composites additive manufacturing, thermoset composites, 1 | INTRODUCTION Additive manufacturing (AM) is the process of depositing material in a layer-by-layer manner through computer control such that the part produced has a three-dimensional structure built from [...]

Loops are prevalent topological structures in cross‐linked polymer networks, resulting from the folding of polymer chains back onto themselves. Traditionally, they have been considered as defects that compromise the mechanical properties of the network, leading to extensive efforts in synthesis to prevent their formation. In this study, we introduce the inclusion of cyclic dibenzo‐24‐crown‐8 (DB24C8) moieties within the polymer network strands to form CCNs, and surprisingly, these loops enhance the mechanical performances of the network, leading to tough elastomers. The toughening effect can be attributed to the unique cyclic structure of DB24C8. The relatively small size and the presence of rigid phenyl rings provide the loops with relatively stable conformations, allowing for substantial energy dissipation upon the application of force. Furthermore, the DB24C8 rings possess a broad range of potential conformations, imparting the materials with exceptional elasticity. The synergistic combination of these two features effectively toughens the materials, resulting in a remarkable 66‐fold increase in toughness compared to the control sample of covalent networks. Moreover, the mechanical properties, particularly the recovery performance of the network, can be effectively tuned by introducing guests to bind with DB24C8, such as potassium ions and secondary ammonium salts. [ABSTRACT FROM AUTHOR]

Vibrations with various frequencies in daily life and industry can cause health hazards and fatigue failure of critical structures, which requires the development of elastomers with high energy dissipation at desired frequencies. Current strategies relying on tuning characteristic relaxation time of polymer chains are mostly qualitative empirical methods, and it is difficult to precisely control damping performances. Here, we report a general strategy for constructing dynamic crosslinked polymer fluid gels that provide controllable ultrahigh energy dissipation. This is realized by dynamic‐bond‐mediated chain reptation of polymer fluids in a crosslinked network, where the characteristic time of chain reptation is dominated by the presence of well‐defined dissociation time of dynamic bonds and almost independent of their molar mass. Using prototypical supramolecular polydimethylsiloxane elastomers, we demonstrate that dynamic crosslinked polymer fluid gels exhibit a controllable ultrahigh damping performance at desired frequencies (10−2~102 Hz), exceeding that of typical state‐of‐the‐art silicone damping materials. Their shock absorption is over 300 % higher than that of commercial silicone rubber under the same impact force. [ABSTRACT FROM AUTHOR]

In this study, a novel iron-based catalyst system, Fe(acac)3/(isocyanoimino) triptenylphosphorane (IITP)/AlR3, was employed for the synthesis of syndiotactic 1,2-polybutadiene in hexane. This catalyst system exhibits remarkably high catalytic activity, achieving a polymerization activity of 762 kgpolymer·molcatalyst−1·h−1 at 50 °C with a [BD]/[Fe] molar ratio of 20000. Furthermore, living polymerization characteristic were observed during the investigation of the polymerization kinetics of 1,3-butadiene polymerization. These characteristics were well demonstrated by a narrow molecular weight distribution (PDI≈2.0) of the resulting polybutadiene and a linear relationship between–ln(1 − c) and polymerization time as well as number average molecular weight and polymer yield. The resultant polymer showed a 1,2-selectivity of approximately 76% and stereoregularity ranging from 62% to 73%(rrrr). Additionally, through kinetic studies on polymerization reaction, an apparent activation energy Ea value of this catalytic system was calculated to be 84.98 kJ·mol−1, which suggests that high polymerization temperature favors efficient polymerization. [ABSTRACT FROM AUTHOR]

The emerging self-healing concept in rubber materials appears to be a good option for reducing rubber waste since it can enhance the longevity of the product's structure in conjunction with standard development goals to ensure sustainable consumption and efficient use of resources. Self-healing elastomers are fabricated to heal cracks and damage both at the micro and macroscopic levels to restrict failure by incorporating healing agents extrinsically or intrinsically. The major successful techniques to fabricate self-healing rubber were reviewed. The review also focuses on testing and analysis methods to understand the healing phenomena and quantification methods to measure the healing performance. The review also includes an overview of the self-healing elastomers for tyre applications. [ABSTRACT FROM AUTHOR]

The aim of this study is to explore a method for modifying waste brick powder (WBP) in order to reapply it to rubber products for effective resource recycling. Firstly, we use the auto polymerization of catechol/polyamine (CPA) on the surface of WBP to form a poly catechol/polyamine (PCPA) coating as an intermediate reaction platform. And then the macromolecular modifier, epoxy-functionalized elastomer (ethylene vinyl acetate-glycidyl methacrylate terpolymer) (EVMG), is further grafted onto the PCPA coating to prepare the WBP@EVMG hybrid materials. During the preparation of the WBP@EVMG hybrid materials, a ring-opening reaction between the amine group of PCPA and the epoxy group of EVMG occurs. The NR/WBP@EVMG composites are prepared by mechanical blending. The interfacial interactions between WBP@EVMG and NR are analyzed and verified in detail by dynamic mechanical analysis (DMA) and rubber process analyzer (RPA). It is shown that the modified NR/WBP composites show increased vulcanization rate and better mechanical properties, and the tensile strength, abrasion resistance, cracking strength, and wet slip resistance of NR/WBP@EVMG-15 are increased by 29%, 6%, 16%, and 11%, respectively, compared with that of NR/WBP composites, which provides a unique idea for the reuse of waste brick powder in rubber. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Poly(3‐hydroxybutyrate), a crucial member of the large biodegradable polyhydroxyalkanoate family, suffers from its brittleness. To enhance its performance, we employed a straightforward approach involving the ring‐opening copolymerization of racemic‐β‐butyrolactone (rac‐β‐BL) and β‐propiolactone (β‐PL) using the syndio‐selective amino‐alkoxy‐bis(phenolate)‐yttrium complex as a catalyst, thanks to the excellent ductility of poly(3‐hydroxypropionate). Control over the rac‐β‐BL/β‐PL feeding ratios and polymerization time yielded random or block copolymers with tunable thermal and mechanical properties comparable to traditional fossil‐based plastics. Furthermore, we achieved one‐pot synthesis of hard‐soft‐hard triblock copolymers by exploiting monomers' different copolymerization rates and a bifunctional initiator, thus transforming polyhydroxyalkanoates from hard and tough plastics to soft and ductile thermoplastic elastomers. [ABSTRACT FROM AUTHOR]

A viscoelastic constitutive model constructed with fractional derivatives can accurately describe the mechanical phenomena caused by materials with time-dependent and memory properties. Using this model, the vibration characteristics and stability of a functionally graded fractional derivative viscoelastic fluid–conveying pipe with initial geometric defects are investigated in this study. First, the differential equation of motion for a functionally graded fractional derivative viscoelastic fluid–conveying pipe with initial geometric defects is derived by applying the Hamilton principle. Dimensionless differential equations and boundary conditions are discretized using a differential quadrature method, and numerical solutions of the equations under three boundary conditions are obtained. Further, the effects of geometric defect types, fractional order, power law exponent, and other factors on the complex frequency of this fluid-conveying pipe are discussed. The findings revealed that the geometric defects of the fluid-conveying pipe can significantly affect the complex frequency of the system. Moreover, the pipe's damping characteristics vary with the fractional order of the viscoelastic material. In other words, the higher the vibration mode of the pipe, the more susceptible it is to the fractional order. Because the fractional derivative relates to values near the current moment and overall history, it can effectively describe the temporal effect of materials, such as polymers, synthetic rubber, and coatings. Many naturally occurring materials (including geological materials such as soil, oil, and minerals and biological materials such as muscle, bone, and blood) exhibit time-dependent properties. The deformation of such materials relates to the current stress level and their overall history. Because the fractional derivative constitutive relation can describe the dynamic properties of a structure in a wide frequency range with only a few parameters and terms, it represents a potential candidate for addressing the mechanical problems of viscoelastic materials and structures. In this study, functionally graded fractional derivative viscoelastic materials were applied to a fluid-conveying pipe with initial geometric curvature, as common in practical engineering. The effects of the initial geometric defect type, dimensionless delay time, power law exponent, and other parameters on the stability of the fluid-conveying pipe were discussed, providing some theoretical reference for the design of such fluid-conveying pipes. [ABSTRACT FROM AUTHOR]

In this study, the vibration characteristics of a bullet-loaded recorder's vibration damping system under various preload conditions are investigated through theoretical analysis, numerical simulations, and experimental verification. The findings indicate that the inclusion of a polyurethane elastomer vibration damping buffer layer between the cartridge and the recorder, along with the application of a specific preload, significantly reduces the amplitude of vibration acceleration transmitted to the recorder's interior. This, in turn, enhances the overload resistance of the cartridge's internal circuit. Numerical simulation results and theoretical analysis suggest that increasing the preload on the buffer material between the elastomer and the recorder reduces both the frequency ratio and damping ratio of the damping system. This reduction further decreases the amplitude of vibration transmitted to the recorder. However, excessively high preload generates substantial compressive stress within the recorder under static conditions, intensifying during the projectile's accelerated movement. As a consequence, deformation and damage occur to the internal circuitry. Therefore, ensuring that the recorder possesses the structural strength necessary to withstand increased preload is crucial. This balancing act improves the recorder's resistance to shock, vibration, and overload, while also preventing excessive stress-induced damage. [ABSTRACT FROM AUTHOR]

Improving the energy efficiency of robots remains a crucial challenge in soft robotics, with energy harvesting emerging as a promising approach to address it. This study presents a functional soft robotic composite called OPV-DEA, which integrates flexible organic photovoltaic (OPV) and dielectric elastomer actuator (DEA). The composite can simultaneously generate electrostatic bending actuation and harvest energy from external lights. Owing to its simplicity and inherent flexibility, the OPV-DEA is poised to function as a fundamental building block for soft robots. This study aimed to validate this concept by initially establishing the fabrication process of OPV-DEA. Subsequently, experimental samples are fabricated and characterized. The results show that the samples exhibit a voltage-controllable bending actuation of up to 15.6° and harvested power output of 1.35 mW under an incident power irradiance of 11.7 mW/cm2. These performances remain consistent even after 1000 actuation cycles. Finally, to demonstrate the feasibility of soft robotic applications, an untethered swimming robot equipped with two OPV-DEAs is fabricated and tested. The robot demonstrates swimming at a speed of 21.7 mm/s. The power consumption of the robot is dominated by a high-voltage DC-DC converter, with a value approximately 1.5 W. As a result, the on-board OPVs cannot supply the necessary energy during locomotion simultaneously. Instead, they contribute to the overall system by charging a battery used for the controller on board. Nevertheless, these findings suggest that the OPV-DEA could pave the way for the development of an unprecedented range of functional soft robots. [ABSTRACT FROM AUTHOR]

Degradable biomedical elastomers (DBE), characterized by controlled biodegradability, excellent biocompatibility, tailored elasticity, and favorable network design and processability, have become indispensable in tissue repair. This review critically examines the recent advances of biodegradable elastomers for tissue repair, focusing mainly on degradation mechanisms and evaluation, synthesis and crosslinking methods, microstructure design, processing techniques, and tissue repair applications. The review explores the material composition and cross-linking methods of elastomers used in tissue repair, addressing chemistry-related challenges and structural design considerations. In addition, this review focuses on the processing methods of two- and three-dimensional structures of elastomers, and systematically discusses the contribution of processing methods such as solvent casting, electrostatic spinning, and three-/four-dimensional printing of DBE. Furthermore, we describe recent advances in tissue repair using DBE, and include advances achieved in regenerating different tissues, including nerves, tendons, muscle, cardiac, and bone, highlighting their efficacy and versatility. The review concludes by discussing the current challenges in material selection, biodegradation, bioactivation, and manufacturing in tissue repair, and suggests future research directions. This concise yet comprehensive analysis aims to provide valuable insights and technical guidance for advances in DBE for tissue engineering. [ABSTRACT FROM AUTHOR]

Five types of magneto‐rheological elastomers (MREs) based on natural rubber were synthesized by incorporating carbonyl iron particles (CIP) as the primary filler. The objective was to investigate the influence of carbon fiber and magnetic particle content on the mechanical and magneto‐rheological properties of the MREs. Carbon fibers (CF) were further added as secondary reinforcement pre‐modified with polydopamine. The composite's microstructure was examined through scanning electron microscopy (SEM), while the mechanical and magnetodynamic properties were assessed using an electronic universal testing machine and an advanced rotational rheometer. The addition of appropriate amounts of CIP and CF resulted in increased rubber modulus, indicating the formation of a filler‐rubber network and the synergistic effect between carbon fibers as a supporting structure and CIP. Compared to the unfilled MREs, the mechanical and magnetodynamic properties were further improved by adding 2 and 4 wt% CF. These findings demonstrate that employing carbon fibers as reinforcing fillers and incorporating suitable magnetic fillers can enhance the magnetic and mechanical properties of the materials, providing a theoretical basis for the study of MREs' performance. Highlights: CF and CIP synergistically enhance the strength of the rubber matrix.The MR effect is gradually enhanced with the increase of CIP content.Modified CF has a promoting effect on the magnetic responsivity.Magnetic responsivity increases with increasing modified CF content.Improved mechanical and magnetodynamic properties of composites. [ABSTRACT FROM AUTHOR]

Polymer‐based thermal interface materials (TIMs) with excellent thermal conductivity and heat dissipation capabilities play a crucial role in addressing the issue of heat accumulation in advanced integrated electronics. However, establishing improved surface interactions and complete networks to enhance efficient phonon transfer remains a significant challenge. To tackle this problem, surface modification and ice‐templating techniques are commonly employed to create the robust interface crosslinks and continuously thermal conductive pathways. Herein, 2‐mercaptobenzimidazole (MB) was used as a reducing and modifying agent to functionalize graphene oxide (rGO‐MB) within the three‐dimensional networks, which was prepared using a combination of hydrothermal and ice‐templating methods. As a result, the reduced graphene oxide/natural rubber (rGO‐MB/NR) TIMs exhibited a remarkable through‐plane thermal conductivity of 0.93 W m−1 K−1 with a filler loading of 3 wt%. The enhanced interface interactions between rGO‐MB and NR, combined with the establishment of a three‐dimensional network, significantly contributed to the improved thermal conductivity and heat dissipation capabilities. Moreover, the obtained TIMs demonstrated favorable mechanical properties (5.06 MPa, 502%) and excellent insulation performance (3 × 1013 Ω cm). These findings provide the valuable insights into potential solutions for mitigating heat accumulation issues in next‐generation electronics. Highlights: rGO‐MB with thiol groups was obtained by the hydrothermal method.Interactions between rGO‐MB and NR mainly depended on the chemical bonds.rGO‐MB/NR TIMs owned the improved thermal management performance. [ABSTRACT FROM AUTHOR]

EPDM, HNBR and FKM materials were exposed at 150 °C to air under atmospheric pressure and to hydrogen at 50 bar for different ageing times. All measurements after hydrogen exposure were conducted on samples in degassed condition to assess irreversible effects resulting from that exposure and to compare them to those after ageing in air. Density, hardness, tensile properties, compression set, and hydrogen permeability of all samples were analysed. In both ageing environments, HNBR exhibited the most significant changes of material properties. However, for both EPDM and HNBR, considerably less severe ageing effects were observed under hydrogen in comparison to ageing in air. On the other hand, FKM showed about the same low level of deterioration in both ageing environments but exhibited poor resistance against damage due to rapid gas decompression in hydrogen environment that can lead to seal failure. The obtained results may serve as a guidance toward a better understanding for design and utilisation of elastomeric materials in future hydrogen infrastructure components. • Three different rubber seal materials. • Ageing up to 100 days at 150 °C under 50 bar hydrogen or under air. • Comparison of ageing effects after equilibration. • Depending on the material the ageing ranged from less severe to equal to air ageing. • Rapid gas decompression became obvious for fluorocarbon rubber. [ABSTRACT FROM AUTHOR]

Helical structures of liquid crystal elastomers (LCEs) hold promise in soft robotics for self‐regulated rolling motions. The understanding of their motion paths and potentials for terrain exploration remains limited. This study introduces a self‐adjusting, lateral‐rolling soft robot inspired by sidewinder snakes. The spring‐like LCE helical filaments (HFs) autonomously respond to thermal cues, demonstrating dynamic and sustainable locomotion with adaptive rolling along non‐linear paths. By fine‐tuning the diameter, pitch, and modulus of the LCE HFs, and the environmental temperature, the movements of the LCE HFs, allowing for exploration of diverse terrains over a 600 cm2 area within a few minutes, can be programmed. LCE HFs are showcased to navigate through over nine obstacles, including maze escaping, terrain exploration, target hunting, and successfully surmounting staircases through adaptable rolling. [ABSTRACT FROM AUTHOR]

With the trend of integration and miniaturization of stretchable electronics, thermal management has been a crucial issue. Developing novel materials with high thermal conductivity (TC) and flexibility is urgent. Herein, we report a stretchable polydimethylsiloxane (PDMS)/boron nitride nanosheet (BNNS)@spherical aluminum oxide (Al2O3) composite with high TC and electrical insulation prepared by a two‐step strategy of sucrose‐template and hot‐pressing. An effective foam‐pressing route benefits the composites to form a three‐dimensional thermally conductive networks, improving the in‐plane TC value of the resultant composite to 4.03 W/(mK) at the filler mass fraction of 35.7 wt% and enhancing to 4.66 W/(mK) under 40% stretching ratio. Meanwhile, the composites can be restored to their former state and retain thermally conductive stability with repeated bending and twisting tests. Moreover, the composites were applied in LED with stretching, exhibiting good heat dissipation performance. These results demonstrate this PDMS composite can be potentially utilized as a high‐performance material to solve thermal management problems in flexible electronics. Highlights: The heat conduction network is prepared by sucrose‐template and hot‐pressing.BNNS@P‐Al2O3 fillers are self‐assembled via the electrostatic interaction.The composites exhibit good thermal conduction and superior flexibility.The thermal conductivity of the composite increases after stretching.The composites can retain thermal conductive stability after deformation. [ABSTRACT FROM AUTHOR]

A porous actuator is prepared using a liquid crystal elastomer (LCE) loaded with metal‐organic framework (MOF) nanoparticles (MIL‐88A). While the swellable MOF additive endows the LCE actuator with nanoscale pores, after its removal by chemical etching, macroporous LCE actuator is obtained. This LCE‐MOF actuator displays several interesting features. 1) Selective etching allows the actuator in water to curl in one direction and then reverse the curling direction owing to differential water absorption of the nano‐ and macroporous layers. 2) The stretching‐induced alignment of mesogens in the actuator is little affected by the presence of MOF and substantially retained after water uptake, so that an actuation deformation can be generated either by water absorption or thermally induced order‐disorder phase transition. 3) Assisted by the UV irradiation used for polymer cross‐linking, magnetic iron oxide FeO appears to be formed after chemical etching, which allows the actuator to gain the ability to move on water surface guided by a magnet. 4) The in situ formation of magnetic iron oxide in the macroporous actuator also provides an enhanced photothermal effect, making light‐driven locomotion of the actuator more effective. The use of active porogen like MOF opens a new way to explore porous LCE actuators. [ABSTRACT FROM AUTHOR]

Understanding viscoelastic behavior of dielectric elastomers for artificial muscle application is important to regulate actuation performance, response time, energy density, sensitivity, duty cycle, etc. The performance of elastomers is widely recognized as being influenced by various fillers, including functional particles and poly-reagents. However, the impact of fillers on the viscoelastic properties of VHB 4910 remains to be fully understood. In this work, a new range of particulate-polymer filled VHB elastomers are studied for the effects of barium titanate and Ketjenblack particles dispersed trimethylolpropane trimethylacrylate on viscoelastic properties. This followed characterization of stress-relaxation and creep behavior to realize the time-dependent mechanical performance. Also, the stress-softening and energy dissipation behavior are examined to find the number of cycles required to reach the equilibrium energy state. Viscoelastic properties of elastomer including elastic modulus, toughness, are found to significantly reduced as a result of modified poroelastic effects due to incorporated fillers. The mechanical properties of composites are evidenced to depend on the size of the particulates and the amount of polymer reagent within elastomer. Theoretical analysis comparing deformation, relaxation, and creep mechanisms in biomedical materials validates the potential of modified elastomers for use in soft actuation devices, particularly in the field of artificial muscles. This work may help in recognizing the strategies to tune viscoelastic behavior of microporous elastomers for potential applications in flexible electronics. [ABSTRACT FROM AUTHOR]

The partial or total replacement of carbon black by silica fillers is initiated through various techniques for environment-friendly, smart, and fuel-efficient NR composites for high-end dynamic applications like tyre tread. The smart properties such as low rolling resistance, better wet skid resistance, and abrasion resistance as well as noise reduction, create tyre tread compounds with superior performance. The endeavour to maximise the incorporation of eco-friendly ingredients like silica filler in rubber compound associates to produce a green tyre product indeed. The present review encompasses those approaches with a substantial contribution in the area along with critical insights in the respective efforts. Initially, the various types of commercially available silica fillers are discussed in brief, followed by the various approaches for surface modification in detail. Finally, the miscellaneous initiatives along with their achievements and drawbacks are included under five strategic verticals for better understanding along with vital remarks. [ABSTRACT FROM AUTHOR]

Biobased thermoplastic polyamide elastomers (TPAEs) have received increasing attention in both academia and industry. Here, a series of semi‐biobased long‐chain TPAEs are successfully synthesized via one‐step melt polymerization, employing polyamide 1210 (PA1210) and polyetheramines (PEAs) as hard and soft segments, respectively. The prepared TPAEs demonstrate excellent mechanical properties, energy dissipation capabilities, low density, good damping, high resilience, and low melting temperature. More interestingly, the properties of the TPAEs can be customized by adjusting the content and molecular weight of PEA. By varying the molecular weights of the PEAs, two different thermal behaviors can be observed in the prepared TPAEs. Specifically, PEA with low molecular weight has good compatibility with PA1210, leading to an increase in the conformation of the crystalline region and a significant decrease in melting temperature. Meanwhile, high molecular weight PEA causes strong phase separation with PA1210, leading to limited crystalline regions and inadequate physical cross‐linking, further resulting in suboptimal mechanical properties. This work provides new insights into the design and preparation of PEA‐type biobased long‐chain TPAEs. [ABSTRACT FROM AUTHOR]

The treatment of waste plastics has gradually become a hot topic in the current scientific community. In response to the needs for high-impact performance R-PP-based composites, carbon fiber (CF)-reinforced polyolefin elastomer (POE)/recycled polypropylene (R-PP) composite (CF/POE/R-PP) was prepared by the mechanical blending method, and its mechanical and thermal properties were systematically studied. It was found that the CF could effectively improve the bending and notch impact strength as well as enhance the thermal stability of POE/R-PP. Furthermore, a stable and dispersed composite interface formed by the combination of maleic anhydride-grafted polypropylene (PP-g-MAH) with the surface of CF and the fusion alkyl chains in R-PP and POE further enhanced the CF's reinforcing effect. As a result, the addition of 9 wt.% CF successfully improved the heat resistance of the composite material, and the residual carbon content increased by 97.84% after sintering. The composite toughening of POE and CF effectively improved the impact strength of the composite material, with a maximum increase of over 1000%. This study ultimately resulted in a high-impact-resistant composite material. [ABSTRACT FROM AUTHOR]

Vulcanization is a chemical modification of rubber that requires a considerable amount of thermal energy. To save thermal energy, the kinetics of rubber vulcanization should be improved. In this article, the curing properties of rubber vulcanization are thoroughly investigated using the moving die rheometer (MDR) technique. To enhance the kinetics in different stages of ZnO-based sulfur vulcanization systems, small amounts of MgO were added. The results revealed that the small amount of 1 to 2 phr (per hundred grams of rubber) of MgO in the controlled 5 phr ZnO-based curing systems can significantly improve the curing kinetics. For example, the optimum curing time of 1 phr MgO added to the 5 phr ZnO-containing semi-efficient vulcanization system at different temperatures was more than half that of the controlled 5 phr ZnO-only compound. While maintaining a similar rate of vulcanization, the vulcanization temperature can be reduced by up to 20 °C by using MgO as a co-cure activator, which exhibits similar or better rheometric mechanical properties compared to the controlled compounds. With the addition of MgO as a co-cure activator, the vulcanization reactions become very fast, enabling vulcanization to be completed, even at the boiling point of water (100 °C) with an affordable curing time (<1 h). By reducing the vulcanization temperature, the scorch safety time can be enhanced in the ZnO/MgO-based binary cure activator-containing vulcanizates. Overall, MgO could be a potential candidate as a co-cure activator with ZnO for the vulcanization of rubber, offering better economical and eco-friendly methods. [ABSTRACT FROM AUTHOR]

It has been recently demonstrated that laser micromachining of magnetoactive elastomers is a very convenient method for fabricating dynamic surface microstructures with magnetically tunable properties, such as wettability and surface reflectivity. In this study, we investigate the impact of the micromachining process on the fabricated material's structural properties and its chemical composition. By employing scanning electron microscopy, we investigate changes in size distribution and spatial arrangement of carbonyl iron microparticles dispersed in the polydimethylsiloxane (PDMS) matrix as a function of laser irradiation. Based on the images obtained by a low vacuum secondary electron detector, we analyze modifications of the surface topography. The results show that most profound modifications occur during the low-exposure (8 J/cm2) treatment of the surface with the laser beam. Our findings provide important insights for developing theoretical models of functional properties of laser-sculptured microstructures from magnetoactive elastomers. [ABSTRACT FROM AUTHOR]

SBS (styrene-butadiene-styrene block copolymer) is a thermoplastic elastomer with properties most similar to rubber. SBS asphalt modifier is mainly composed of a styrene-butadiene-styrene block copolymer with a certain amount of additives and stabilizers. SBS-modified asphalt binder has always been the most commonly used pavement material both domestically and internationally. However, conventional wet-process SBS-modified asphalt binder requires manufacturers to produce it in advance and transport it to a mixing plant for blending. This has provided an opportunity for unscrupulous businesses to reduce the amount of SBS by adding other substances, allowing inferior asphalt binder to pass inspections undetected. At the same time, conventional wet-process SBS-modified asphalt tends to undergo phase separation and experience a decline in performance as the storage time increases. However, dry-process SBS-modified asphalt can be directly added at the mixing plant, effectively addressing the issues associated with conventional wet-process SBS-modified asphalt. It also helps to reduce environmental pollution to a certain extent. This study investigates the extraction process of dry-process SBS-modified asphalt binder. It clarifies the performance and modification mechanisms of two types of dry-process SBS-modified asphalt binder at different dosages through various testing methods, including basic indicators, rheological properties, infrared spectroscopy, and fluorescence microscopy. The results indicate that due to the incorporation of oil, crosslinker, solubilizer, and other substances into dry-process SBS modifier, there is a small amount of chemical reaction with asphalt in the melting process. The high- and low-temperature properties and fatigue properties of the two dry-process SBS-modified asphalt binders at a 7% dosage are close to wet SBS-modified asphalt binder at a 5% dosage. [ABSTRACT FROM AUTHOR]

The sensor response of pressure-sensitive conductive elastomers using polymeric materials can be adjusted by altering the type and quantity of fillers used during manufacturing. Another method involves modifying the surface shape of the elastomer. This study investigates the sensor response by altering the surface shape of an electrode using a readily available pressure-sensitive conductive elastomer. By employing an oxygen-free copper electrode with a flat surface (with surface roughness parameters Ra = 0.064 μm and Rz = 0.564 μm) as a baseline, we examined the sensor system's characteristics. Electrodes were fabricated with triangular wave concavo-convex surfaces, featuring tip angles of 60, 90, and 120°. Improved sensor responses were observed with electrodes having tip angles of 60 and 90°. Additionally, even with varying conductive properties of elastomers, the conductance of the elastomer sensor increased similarly when using an electrode with a 90° tip angle. This study demonstrates the potential for expanding the applications of conductive elastomer sensors, highlighting the noteworthy improvement in sensor response and performance achieved by altering the surface shape of electrodes used with commercially available conductive elastomers. [ABSTRACT FROM AUTHOR]

In recent years, soft robotic sensors have rapidly advanced to endow robots with the ability to interact with the external environment. Here, we propose a polymer optical fiber (POF) sensor with sensitive and stable detection performance for strain, bending, twisting, and pressing. Thus, we can map the real-time output light intensity of POF sensors to the spatial morphology of the elastomer. By leveraging the intrinsic correlations of neighboring sensors and machine learning algorithms, we realize the spatially resolved detection of the pressing and multi-dimensional deformation of elastomers. Specifically, the developed intelligent sensing system can effectively recognize the two-dimensional indentation position with a prediction accuracy as large as ~99.17%. The average prediction accuracy of combined strain and twist is ~98.4% using the random forest algorithm. In addition, we demonstrate an integrated intelligent glove for the recognition of hand gestures with a high recognition accuracy of 99.38%. Our work holds promise for applications in soft robots for interactive tasks in complex environments, providing robots with multidimensional proprioceptive perception. And it also can be applied in smart wearable sensing, human prosthetics, and human–machine interaction interfaces. [ABSTRACT FROM AUTHOR]

Polyurethanes (PUs) are versatile polymers used in industries at large scale. PUs are in used in the form of foam, elastomers, adhesives, fibers, thermosets, thermoplastics, etc. Polyols and isocyanates are the two compounds used to synthesize PU. Day by day increasing price of crude oil and its destructive impact on the environment motivate researchers to develop bio‐PU. Seed oils are attracting nowadays because of their renewability and low cost. They are the best substitutes for fossil fuel‐based polyol used in the preparation of PUs. However, these bio‐based PUs show lower thermal, mechanical properties, which needs improvement to further their utilization. The need to maintain a cleaner environment for the survival of both aquatic and terrestrial lives including human beings is very crucial and is a subject of increasing concern to the environmentalists. The removal of heavy metals, dyes, and organic pollutants from wastewater before their discharge in the environmental is very important due to its polluting effect on the underground water. This review article emphasizes on to provide insight on the developments in the field of chemistry, types, and synthesis of various PUs, as well as on the components used to synthesize bio‐based PUs and water treatment applications. Additionally, details on the PU's environmental friendliness are highlighted, with a focus on their potential to recycling and recovery. This review also highlights the details of the synthesis, uses, and potential futures of PU composites. [ABSTRACT FROM AUTHOR]

Inorganic nanoparticles have been widely used as fillers to modify dielectric elastomers to simultaneously improve mechanical and dielectric performances. Elegant interface design is crucial for achieving synergy between fillers and elastomers. Herein, we show that diborate ester polymers can both improve the interfacial compatibility between inorganic nanoparticles and elastomers and enhance the dielectric performances. The diborate ester polymers are derived from the condensation reaction between tetrakis(dimethylamino)diborane (or tetrahydroxydiborane) and a three‐armed catechol monomer. Choosing TiO2 nanoparticles as the inner core, a series of TiO2@diborate ester polymer core‐shell nanoparticles are synthesized. Density functional theory (DFT) calculations indicate that the diborate ester polymer shell tightly bonds to the surface of TiO2 through two dissociative bidentate bridging modes of the catechol monomer (absorption energy: −11.049 eV). These core‐shell nanoparticles can soften and tough polydimethylsiloxane (PDMS) and show enhanced interfacial binding affinity to PDMS than naked TiO2 nanoparticles. The fabricated composites have high dielectric constants (up to 6.8) and low dielectric losses (<0.03). The actuated strain and puncture voltage of the composites reach 25.9% and 80 V μm−1, respectively, which are much higher than those of PDMS and TiO2/PDMS. This work provides a promising route to fabricate core‐shell nanoparticles for high‐performance dielectric elastomers. [ABSTRACT FROM AUTHOR]

The properties and practical applications of polyethylene are closely associated with the polymer molecular weight, polydispersity, degree of branching, and the type of branches and its arrangement within microstructure. In this study, a set of structurally diverse unsymmetrical 1‐(2,6‐dibenzhydryl‐4‐hydroxylphenylimino)‐2‐(2,6‐(R)‐4‐(R1)phenylimino)acenaphthene‐nickel dibromide precatalysts (where Ni2Me [R = Me, R1 = H], Ni2Et [R = Et, R1 = H], Ni2iPr [R = iPr, R1 = H], Ni3Me [R, R1 = Me], Ni2Et,Me [R = Et, R1 = Me]) has been prepared and studied for ethylene polymerization. Molecular structure analysis of Ni2Me and Ni2Et complexes revealed distorted tetrahedral geometries at nickel. The polymerization activities are extremely high for all precatalysts upon activation with either EASC or MMAO aluminum reagents, a trend notably pronounced in the case of the EASC‐activated systems, entering activity in the range of 10 million g mol−1 h−1 at 30°C. The Ni2Me demonstrated exceptional performance at higher temperatures, achieving an activity of 2.4 × 106 g mol−1 h−1 at 100°C and generated high molecular weight polyethylene (Mw = 105 g mol−1) with narrow polymer dispersity across all reaction temperatures (Ð ≈ 1.5). High temperature 13C NMR spectra identified 97–142/1000C branches in resulting polyethylene, a feature significantly dependent on the reaction temperature. In terms of mechanical properties, stress–strain analysis indicated that polyethylene synthesized at lower temperatures displayed superior tensile strength compared with that produced at higher reaction temperatures, while a reverse trend was observed in strain recovery analysis. The high strain recovery (up to 72%) of these polyethylene highlights the characteristic properties of thermoplastic elastomers. [ABSTRACT FROM AUTHOR]

Background: One of the biggest challenges in soft robotics is the variability and controllability of stiffness. Jamming-based approaches have been of interest to change stiffness dramatically by increasing friction between grains, layers, or fibers. Besides, magnetorheological elastomers (MREs) that exhibit magnetic field-dependent viscoelasticity have significant potential as a stiffness variation material. This study investigates the unique mechanics of magnetic jamming of MRE sheets exploring stiffness change both due to jamming and variable viscosity. Methods: Sample MREs and flexible neodymium-iron-boron (NdFeB) magnets are manufactured. Uniaxial tensile tests supported with digital image correlation are performed to characterize the materials. Multi-layer jamming structures comprised of MREs and NdFeB magnets are developed and validated through 3-point bending experiments and finite element simulations. Results: Results show that the stiffness of the multi-layer structure is higher under magnetic field. Furthermore, the stiffness change is increased when MREs are used instead of PDMS as layers. Conclusion: This study proves the concept of magnetic jamming of MRE layers. The results are crucial for the possible soft robotic implementation of the proposed hybrid stiffening approach combining jamming with viscoelasticity modification. [ABSTRACT FROM AUTHOR]

[Display omitted] In this research, new injectable and in situ photocurable elastomeric nanohybrids have been fabricated from polyalphaolefin (PAO) resins and halloysite nanofiller. In this regard, the co-oligomerization of long α-olefin monomers (C6, C8 and C10) with alkenol counterparts was carried out via a simple cationic route to provide OH-functionalized PAOs. The newly formed PAO type copolymer resins as well as halloysite nanoclay were then equipped with photocurable C C bonds containing an acrylate moiety. After the characterization of the final chemical substances and also of the intermediate structures, experimentally and computationally by means of Density Functional Theory (DFT) calculations, the neat treated PAO and PAO/halloysite nanohybrids were subjected to a curing process by visible light irradiation (λ ∼ 475 nm, blue light). The crosslinking efficiency of the neat resins and the formed nanohybrid was evaluated using shrinkage strain–time curves and equilibrium swelling method. The suggested nanohybrid is not only biocompatible (96 % in the MTT assay), and hydrophilic (with a water contact angle of 61°), but also exhibits an easy, fast and robust curing process with great potential for coating and sealing technologies for medical devices. [ABSTRACT FROM AUTHOR]

To address the concern that biodegradable elastomers are environmental-friendly but usually associated with poor properties for practical utilization, we report a star-crosslinked poly(ethylene glycol-glycerol-itaconate-sebacate) (PEGIS) elastomer synthesized by esterification, polycondensation and UV curing, and reinforced by bacterial cellulose (BC). The interpenetrating network of primary BC backbone and vulcanized elastomer is achieved by the "in-situ secondary network construction" strategy. With the well dispersion of BC without agglomeration, the mechanical properties of PEGIS are significantly enhanced in tensile strength, Young's modulus and elongation at break. The reinforcement strategy is demonstrated to be efficient and offers a route to the development of biodegradable elastomers for a variety of applications in the future. [ABSTRACT FROM AUTHOR]

The limited capacity of typical materials to resist stress loading, which affects their mechanical performance, is one of the most formidable challenges in materials science. Here, we propose a bone-inspired stress-gaining concept of converting typically destructive stress into a favorable factor to substantially enhance the mechanical properties of elastomers. The concept was realized by a molecular design of dynamic poly(oxime-urethanes) network with mesophase domains. During external loading, the mesophase domains in the condensed state were aligned into more ordered domains, and the dynamic oxime-urethane bonds served as the dynamic molecular locks disassociating and reorganizing to facilitate and fix the mesophase domains. Consequently, the tensile modulus and strength were enhanced by 1744 and 49.3 times after four cycles of mechanical training, respectively. This study creates a molecular concept with stress-gaining properties induced by repeated mechanical stress loading and will inspire a series of innovative materials for diverse applications. [ABSTRACT FROM AUTHOR]

The mechanical‐electromagnetic dual healing system equips warships with the same reproducibility as biological skin, enabling rapid restoration of electromagnetic stealth and overcoming disturbances in the marine environment. However, the principle of electromagnetic wave absorption (EWA) property regeneration and co‐healing model are still largely unknown. Herein, a bio‐inspired intelligent elastomer is created that combines 2D EWA mediums with an underwater self‐healing fluoropolymer framework, realizing multifunctional integration. It demonstrates excellent broadband EWA characteristics (8.68 GHz, 2.16 mm) and promising underwater self‐healing (23.73%, 3 h). Notably, the dynamic interweaving motion between chemical and physical fields (i.e., dielectric and magnetic fields) facilitates positive chain effects of mechanical healing on electromagnetic function. Consequently, this interdependence drives efficient EWA property regeneration (94.1%, 3 h), including but not limited to underwater and air. Furthermore, the system boasts excellent hydrophobicity and chemical stability for seawater and strong alkali. Overall, this work is the first to present an effective strategy for quickly restoring electromagnetic stealth in marine environments, which expands the feasibility boundary of the interdisciplinarity. [ABSTRACT FROM AUTHOR]

The structural and electro-thermophysical characteristics of organosilicon elastomers modified with multilayer carbon nanotubes (MWCNTs) synthesized on Co-Mo/Al2O3-MgO and metallic (Cu or Ni) microparticles have been studied. The structures were analyzed with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDX). The main focus of this study was the influence of metallic dispersed fillers on the resistance of a modified elastomer with Cu and Ni to the degradation of electrophysical parameters under the action of applied electrical voltage. The distribution of the temperature field on the surface of a modified polymer composite with metallic micro-dimensional structures has been recorded. The collected data demonstrate the possibility of controlling the degradation caused by electrical voltage. It has been found that repeated on/off turns of the elastomer with an MWCNTs on 50 and 100 cycles leads to a deterioration in the properties of the conductive elastomer from the available power of 1.1 kW/m2 (−40 °C) and, as a consequence, a decrease in the power to 0.3 kW/m2 (−40 °C) after 100 on/off cycles. At the same time, the Ni additive allows increasing the power by 1.4 kW/m2 (−40 °C) and reducing the intensity of the degradation of the conductive structures (after 100 on/off cycles up to 1.2 kW/m2 (−40 °C). When Ni is replaced by Cu, the power of the modified composite in the heating mode increases to 1.6 kW/m2 (−40 °C) and, at the same time, the degradation of the conductive structures in the composite decreases in the mode of cyclic offensives (50 and 100 cycles) (1.5 kW/m2 (−40 °C)). It was found that the best result in terms of heat removal is typical for an elastomer sample with an MWCNTs and Cu (temperature reaches 93.9 °C), which indicates an intensification of the heat removal from the most overheated places of the composite structure. At the same time, the maximum temperature for the Ni additives reaches 86.7 °C. A sample without the addition of a micro-sized metal is characterized by the local unevenness of the temperature field distribution, which causes undesirable internal overheating and destruction of the current-conducting structures based on the MWCNTs. The maximum temperature at the same time reaches a value of 49.8 °C. The conducted studies of the distribution of the micro-sizes of Ni and Cu show that Cu, due to its larger particles, improves internal heat exchange and intensifies heat release to the surface of the heater sample, which improves the temperature regime of the MWCNTs and, accordingly, increases resistance to electrophysical degradation. [ABSTRACT FROM AUTHOR]

The performance of silicone rubber gel elastomers is affected by the composition and structure of the crosslinker. In this work, a two-component addition liquid silicone rubber gel material was developed, and the effects of the contents of two methyl hydro-silicone oils on the compression modulus and breakdown strength of the silicone rubber gel insulating material, as well as the performance change after hot air aging at different times (24 h, 48 h, 72 h, 96 h, 120 h, 144 h, 168 h), were studied. The results showed that the breakdown strength and compression modulus exhibited an upward trend with the increase in the hydrogen silicone oil content. The best performance was achieved in the silicone rubber gel with Si-H:Si-Vi = 1.4:1. Moreover, with the increase in aging time, the breakdown strength decreased and the compression modulus increased. [ABSTRACT FROM AUTHOR]

An ideal vascular phantom should be anatomically accurate, have mechanical properties as close as possible to the tissue, and be sufficiently transparent for ease of visualization. However, materials that enable the convergence of these characteristics have remained elusive. The fabrication of patient‐specific vascular phantoms with high anatomical fidelity, optical transparency, and mechanical properties close to those of vascular tissue is reported. These final properties are achieved by 3D printing patient‐specific vascular models with commercial elastomeric acrylic‐based resins before coating them with thiol‐based photopolymerizable resins. Ternary thiol‐ene‐acrylate chemistry is found optimal. A PETMP/allyl glycerol ether (AGE)/polyethylene glycol diacrylate (PEGDA) coating with a 30/70% AGE/PEGDA ratio applied on a flexible resin yielded elastic modulus, UTS, and elongation of 3.41 MPa, 1.76 MPa, and 63.2%, respectively, in range with the human aortic wall. The PETMP/AGE/PEGDA coating doubled the optical transmission from 40% to 80%, approaching 88% of the benchmark silicone‐based elastomer. Higher transparency correlates with a decrease in surface roughness from 2000 to 90 nm after coating. Coated 3D‐printed anatomical replicas are showcased for pre‐procedural planning and medical training with good radio‐opacity and echogenicity. Thiol‐click chemistry coatings, as a surface treatment for elastomeric stereolithographic 3D‐printed objects, address inherent limitations of photopolymer‐based additive manufacturing. [ABSTRACT FROM AUTHOR]

Joint movement is a plentiful source of energy in living organisms; however, it is challenging to harvest due to its multidirectional nature, and effective technologies for harnessing this energy are lacking. In this study, a novel approach is presented to harvest joint motion energy by combining an alternating current dielectric elastomer generator (AC‐DEG) with an electret nanogenerator (ENG). The ACENG‐DEG, utilizing ion hydrogel electrodes and ENG, exhibits remarkable stretchability (860%) and efficiently converts mechanical energy into electrical energy through a stretch‐based mechanism. With only 37 cycles, the device reaches a saturation voltage of 1.18 kV and generates an output charge of 1.96 µC per cycle. Notably, the charge output response speed is approximately four times faster than that of traditional AC‐DEGs. The proposed strategy for harvesting human mechanical energy in this study represents a promising pathway for developing high‐performance energy harvesting devices and self‐powered systems. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers (LCEs) are shape-morphing materials that demonstrate reversible actuation when exposed to external stimuli, such as light or heat. The actuation's complexity depends heavily on the instilled liquid crystal alignment, programmed into the material using various shape-programming processes. As an unavoidable part of LCE synthesis, these also introduce geometrical and output restrictions that dictate the final applicability. Considering LCE's future implementation in real-life applications, it is reasonable to explore these limiting factors. This review offers a brief overview of current shape-programming methods in relation to the challenges of employing LCEs as soft, shape-memory components in future devices. Liquid crystal elastomers are shape-morphing materials that demonstrate reversible actuation when exposed to external stimuli, and their actuation depends heavily on the liquid crystal alignment programmed into these materials, using various shape-programming processes. Here, the author reviews current shape-programming methods in relation to the challenges of employing liquid crystal elastomers as soft, shape-memory components in devices in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] N -(1,3-dimethylbutyl)- N ′-phenyl- p -phenylenediamine quinone (6PPDQ) has attracted significant attention due to its highly acute lethality to sensitive salmonids. However, studies investigating the mechanisms underlying its acute toxicity have been lacking. In this work, we demonstrated the sensitivity of rainbow trout to 6PPDQ-induced mortality. Moribund trout exhibited significantly higher brain concentrations of 6PPDQ compared to surviving trout. In an in vitro model using human brain microvascular endothelial cells, 6PPDQ can penetrate the blood–brain barrier and enhance blood–brain barrier permeability without compromising cell viability. The time spent in the top of the tank increased with rising 6PPDQ concentrations, as indicated by locomotion behavior tests. Furthermore, 6PPDQ influenced neurotransmitter levels and mRNA expression of neurotransmission-related genes in the brain and exhibited strong binding affinity to target neurotransmission-related proteins using computational simulations. The integrated biomarker response value associated with neurotoxicity showed a positive linear correlation with trout mortality. These findings significantly contribute to filling the knowledge gap between neurological impairments and apical outcomes, including behavioral effects and mortality, induced by 6PPDQ. [ABSTRACT FROM AUTHOR]