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This study presents a numerical investigation into the crack tip fields in liquid crystal elastomers (LCEs) using finite element simulations. LCEs exhibit unique mechanical behaviors, such as soft elasticity and directionally adjustable anisotropy, due to the coupling between the deformation of polymer networks and the rotation of liquid crystal mesogens. The numerical simulations focus on a rectangular LCE plate with a small central crack, subjected to uniform stretching. Simulation results reveal the presence of a uniaxial stress state near the crack tip and a universal stress singularity obeying a power law with an exponent of −1. Along the circumferential direction around the crack tip, the stress distribution exhibits a prominent polarization, with the polarization direction precisely aligned with the initial mesogen orientation. For the mesogen reorientation at the crack tip, two types of mesogen rotation—rigid body rotation with the polymer network and relative rotation due to network stretching—are distinguished. The rigid body rotation is found to cause significant heterogeneity in mesogen orientation at the crack tip, but the relative rotation tends to make the mesogen orientation more uniform, generally aligning with the direction of applied stretch. The final mesogen orientation, determined by the initial orientation and rotation, is closely related to the magnitude of the stress field at the crack tip. These findings provide valuable insights into the fracture behavior of LCEs and can serve as a foundation for future experimental and theoretical studies. 

Abstract Radiative cooling has been recently intensively explored for thermal management and enhancing energy efficiency. Yet, traditional materials with singular emissivity fall short in dynamic thermal management, highlighting the need for materials that can adjust their thermal radiation in real time. Active modulation methods, requiring external stimuli such as mechanical stretch, electric potential, or humidity change, offer adaptability but can increase energy use and complexity. Passive approaches, using materials' inherent thermal‐responsive properties, face manufacturing and scalability challenges. Here, a scalable yet effective passive approach is introduced for adaptive thermal modulation based on gold (Au) and liquid crystal elastomer (LCE) with a reversible response to environmental temperature changes. This modulator enables a “low thermal resistance” state through actuation‐induced microcracks that expose a high‐emissivity polymer substrate, and a “high thermal resistance” state by closing these microcracks and forming a high thermal resistance air gap between the modulator and the target object. The flexible design and fixed external dimensions of the Au‐LCE thermal modulator make it adaptable to various surface geometries. Furthermore, by adjusting the LCE's chemical composition, the modulator's transition temperature can be tailored, broadening its applications from enhancing building energy efficiency to improving clothing thermal comfort. 

Abstract In this work, a systematic investigation is conducted on stress‐assisted erosion of the photocurable and degradable elastomer poly(glycerol sebacate) acrylate (PGSA). Without external stress, it is confirmed that the elastomer undergoes surface erosion in an aqueous environment. Upon the application of mechanical stress, the results revealed that the surface erosion rate is dramatically accelerated. By studying the stress corrosion cracking (SCC) phenomena, it is demonstrated that the crack growth speed depends on the applied load and is significantly faster than the surface erosion rate of the elastomer. It is further shown that with decreasing the cross‐link density of the elastomer, the crack growth speed during SCC can be slowed down due to the increased viscoelasticity of the material. 

Abstract The realization of low thermal conductivity at high temperatures (0.11 W m⁻¹K⁻¹800 °C) in ambient air in a porous solid thermal insulation material, using stable packed nanoparticles of high‐entropy spinel oxide with 8 cations (HESO‐8 NPs) with a relatively high packing density of ≈50%, is reported. The high‐density HESO‐8 NP pellets possess around 1000‐fold lower thermal diffusivity than that of air, resulting in much slower heat propagation when subjected to a transient heat flux. The low thermal conductivity and diffusivity are realized by suppressing all three modes of heat transfer, namely solid conduction, gas conduction, and thermal radiation, via stable nanoconstriction and infrared‐absorbing nature of the HESO‐8 NPs, which are enabled by remarkable microstructural stability against coarsening at high temperatures due to the high entropy. This work can elucidate the design of the next‐generation high‐temperature thermal insulation materials using high‐entropy ceramic nanostructures. 

Abstract The fabrication of pressure sensitive adhesives (PSAs) using liquid crystal elastomers (LCEs), which are known for their excellent dissipation properties, is explored in this work. The adhesive properties of the PSAs are evaluated using the 180° peeling test at various conditions. The performance of the LCE adhesives is found to show significant rate and temperature dependence. When the adhesion energy is plotted against the rate, LCE shows an anomalously large power law exponent (n≈ 1.17) compared to existing PSAs (n≈ 0.1–0.6). The unusual rate sensitivity is hypothesized to originate from the synergy of soft elasticity and non‐linear viscoelasticity. The adhesive properties at various rates and temperatures are correlated to the results from dynamic mechanical analysis. Moreover, the large strain stiffening behavior of LCE under uniaxial tension reveals the distinctive advantages offered by LCE as adhesives. Time‐temperature superposition is used to obtain a master curve of adhesion energy that spans rates beyond typical experimental limits. The extreme rate dependence and the large strain stiffening of LCE yield a new category of adhesives that possess special properties, such as reversible adhesion and impact resistance, unlike traditional adhesives.