Supramolecular hydrogels constructed through various host–guest interactions have attracted tremendous attention in view of their excellent dynamic and multi-stimuli responsive performances. Herein, benzyl (Bn) and azobenzene (Azo) grafted poly(ionic liquid)s (PILs) were prepared via a one-pot post-synthesis strategy. By virtue of the difference in binding affinity of Azo and Bn groups with the host compound cucurbituril [8] urea (CB[8]), the newly-developed supramolecular hydrogels exhibited distinctive photo- and thermo-responsive behaviors. Under UV light irradiation, PIL-Azo-Bn/CB[8] hydrogel got weaker, while a gel-to-sol transition was observed when treated by heating. Moreover, the above tunable behaviors were highly reversible. Variable-temperature measurements such as proton nuclear magnetic resonance and ultraviolet–visible spectroscopy illustrated that the photo- and thermo-regulated performances of PIL hydrogel were ascribed to the hierarchical host–guest interactions. As a prototype application in smart circuits, PIL hydrogel exhibited a photo- and thermo-tuned conductivity. Thus, our finding presented a novel and versatile platform to fabricate responsive functional hydrogels via host–guest interactions, which has great promising applications in smart materials and flexible sensors.

中文翻译：

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由分层主客体相互作用调节的光和热响应聚（离子液体）水凝胶


通过各种主客体相互作用构建的超分子水凝胶因其优异的动态和多刺激响应性能而引起了极大的关注。在此，通过一锅后合成策略制备了苄基（Bn）和偶氮苯（Azo）接枝聚（离子液体）（PIL）。由于偶氮基和硼基与主体化合物葫芦脲[8]脲（CB[8]）的结合亲和力不同，新开发的超分子水凝胶表现出独特的光响应和热响应行为。在紫外光照射下，PIL-Azo-Bn/CB[8]水凝胶变弱，而在加热处理时观察到凝胶到溶胶的转变。此外，上述可调行为是高度可逆的。质子核磁共振和紫外可见光谱等变温测量表明，PIL 水凝胶的光调节和热调节性能归因于分层的主客体相互作用。作为智能电路中的原型应用，PIL 水凝胶表现出光和热调节的导电性。因此，我们的发现提出了一种新颖且多功能的平台，可以通过主客体相互作用制造响应性功能水凝胶，这在智能材料和柔性传感器中具有广阔的应用前景。