The photonic color-changing function of chameleons can be achieved by bionic soft-active photomechanochemically responsive cholesteric liquid crystal elastomers.

wide ranging applications have gained increasing interest in the past two decades. These 3D PhC nanostructures possess the feature of periodicity near to the order of light wavelength in the medium; this leads to the localization of light wave in some spectral regions, thereby causing the so-called photonic bandgap (PBG), whose property enables the control of the optical path, polarization, and amplitude of the light. [4-11] The diverse ways by which light wave manipulation can be conducted in the 3D PhCs are vital to fundamental pursuits as well as applications in physical, chemical, biological, and engineering sciences. However, the challenge of realizing this kind of 3D nanostructural PhCs simultaneously with various advantages, such as photonic structures that are operable in a wide optical range, sufficient structural integrity, significant mechanical deformation, stable thermal performance, even relatively low cost, and ease of processing, is high especially considering the existing nanotechnology. [12] In addition, in order to achieve the operational window of PhCs into the UV-vis spectral range (100-700 nm), the lattice constants must be reduced accordingly, and the constituent material should have sufficiently high refractive index. [13-20] Enhancing or discovering unknown properties in PhC materials is expected to advance science. Particularly, high elasticities are critical for the versatility of structural-colored soft PhCs. [21] The mechanical stimuli can readily modulate the arrangement of PhC architecture and directly induce the variation in periodic lattice constants and the reflective color. The mechanochromism of structural-colored materials, including hydrogels, elastomers, and polymers, has been developed and applied in various fields for decades. [22-24] However, their fabrication manners are usually complicated and associated color performances must be improved. Ordered soft matters, such as liquid crystals (LCs), liquid crystalline gels, and liquid crystalline polymers, are one of best candidates to create soft PhCs with advantages of easy fabrication of desired periodic nanostructures, higher refractive index, improved color performance, and high sensitivity to external stimuli. [25-30] Among these soft matters, liquid crystalline polymers with rubber-like elasticity exhibit rich new physics, such as anisotropic soft elasticity, and are considered promising materials in novel technologies. Recent reports using stretchable nematic, chiral nematic, and smectic Given that it is a potential medium for 3D manipulation of photons in the forward-looking technology of quantum optics, nonlinear optics, electronics, nanomaterials, and bionics, 3D photonic crystal (PhC) is a promising material of strategic significance and has great impact on scientific development. Blue phase (BP), a liquid crystalline mesophase with unique nanoscaled 3D PhC features, has been shown to contain significant potential values in fundamental studies and technological applications. However, thus far, the environmental sta...

Ultrasonic welding is attracting increasing attentions in lithium battery joining in the field of battery electric vehicle manufacturing. A three-dimensional finite element model was constructed to study the temperature distribution and heat generation in ultrasonic welding process. Numerical analysis showed that heat generation from plastic deformation accounts for nearly a quarter of the whole heat generation (material plastic deformation and interface friction). The fraction changes little with different sequence of specimens. The highest temperature locates at the contact interface of specimens and it is much lower than the melting point of the joining materials. Temperature distribution of the structure is not symmetric, and there are abnormal points under the effect of serrated ridges of sonotrode tip. Welding process can be divided in to three periods based on temperature evolution on the contact interface of lower specimen. The proposed model is validated by comparing simulated temperature evolution with experimental result.

Traditional electrochromic devices change the color of electrochromic materials by mainly transforming the absorption band of the materials electrically, which leads to low schedulable color selection and color performance of such materials after electrochromism. Although the addition of an interference‐enhanced nanocavity can improve this issue, achieving full‐color controllability on a single electrochromic device is still a huge challenge. This study first demonstrates a near‐full‐color tunable chiroptical electrothermochromic device using a supramolecular chiral photonic material called ferroelectric liquid crystal (FLC)‐doped cholesteric liquid crystal (CLC) (FLC‐CLC). Experimental results show that the pitch of the CLC can be elongated significantly by doping a low concentration of FLC (≈4 wt%) such that the photonic bandgap (PBG) redshifts from blue to the shortwave near‐infrared region at near room temperature. Based on this fascinating feature, the PBG of the FLC‐CLC can be tuned electrically over the entire visible region with high color performance at near room temperature in a low‐voltage range (≤3 V) via the efficient electrothermal effect of the indium‐tin‐oxide‐coated substrate of the sample. Two potential low‐voltage tunable applications based on electrothermochromic FLC‐CLC materials, namely, a broadband tunable laser and a near‐full‐color tunable coaxial microfibric textile, are demonstrated in the study.