Inspired by the stimuli-responsive ability of biological, a variety of hydrogel have been prepared by stimulus, showing great application value in actuators, soft robots, etc. However, it is still challenging to prepare a toughness hydrogel by the way of stimuli-responsive. Herein, we constructed a novel dual-network structure PNIPAM/PVA hydrogel using reversible molecular configuration conversion of PNIPAM chains. Under the stimulus of ethanol, the elastic modulus of PNIPAM/PVA hydrogel can be increased by 47 times (5 times the change of the modulus of sea cucumbers’ tissue) and the stress can be six times of the original. The dynamic borate ester bond formed by the cross-linking of PVA and borax in the hydrogel enables rapid self-healing (η > 99%) within three minutes without external stimulus in the natural environment. In addition, PNIPAM/PVA hydrogels also showed outstanding underwater reversible thermokinetic properties (>25°) based on the hydrophilic/hydrophobic conversion of PNIPAM under thermal stimulation. The successful preparation of ethanol stimulus-enhancing self-healing PNIPAM/PVA hydrogel actuators, provides a new idea for the development of the soft underwater robots.
Jian-Qiang Zhao,Yue-Yu Ma,Xue-Jie Zhao,Yu-Jia Gao,Zi-Yan Xu,Pan-Chao Xiao,Cheng-Yang Yue,Xiao-Wu Lei
Intelligent stimuli-responsive fluorescence materials are extremely pivotal for fabricating luminescent turn-on switching in solid-state photonic integration technology, but it remains a challenging objective for typical 3-dimensional (3D) perovskite nanocrystals. Herein, by fine-tuning the accumulation modes of metal halide components to dynamically control the carrier characteristics, a novel triple-mode photoluminescence (PL) switching was realized in 0D metal halide through stepwise single-crystal to single-crystal (SC-SC) transformation. Specifically, a family of 0D hybrid antimony halides was designed to exhibit three distinct types of PL performance including nonluminescent [Ph3EtP]2Sb2Cl8 (1), yellow-emissive [Ph3EtP]2SbCl5·EtOH (2), and red-emissive [Ph3EtP]2SbCl5 (3). Upon stimulus of ethanol, 1 was successfully converted to 2 through SC-SC transformation with enhanced PL quantum yield from ~0% to 91.50% acting as “turn-on” luminescent switching. Meanwhile, reversible SC-SC and luminescence transformation between 2 and 3 can be also achieved in the ethanol impregnation–heating process as luminescence vapochromism switching. As a consequence, a new triple-model turn-on and color-adjustable luminescent switching of off–onI–onII was realized in 0D hybrid halides. Simultaneously, wide advanced applications were also achieved in anti-counterfeiting, information security, and optical logic gates. This novel photon engineering strategy is expected to deepen the understanding of dynamic PL switching mechanism and guide development of new smart luminescence materials in cutting-edge optical switchable device.
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