The high spatiotemporal resolution of light as an external stimulus allows the control of shape, mechanical properties, and even forces generated by photoresponsive soft materials. For this purpose, supramolecular systems that respond readily and reversibly to photoirradiation and convert microscopic changes into macroscopic effects are needed. This work demonstrates the reversible light-responsive modulation of the osmotic pressure of an aqueous solution of an azobenzene-containing polymer (azopolymer) and α-cyclodextrin. Osmometry shows that this multivalent and photoresponsive host–guest complex can be used to modulate the concentration of solutes in the solution. Upon alternating irradiation with UV and blue light, the osmolality is reversibly switched by 28 mOsm kg^–1. The switching amplitude increases linearly with the concentration of azopolymer and cyclodextrin. This drastic change in osmotic pressure is achieved by carefully designing an azopolymer that provides multivalent interactions as well as high water solubility. In this way, our study demonstrates a tunable control of colligative properties by photoinduced modulation of supramolecular interactions.

中文翻译：

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通过大分子主客体相互作用对渗透压的可逆光响应调制

光作为外部刺激的高时空分辨率允许控制光响应软材料产生的形状、机械性能甚至力。为此，需要能够对光辐照容易且可逆地响应并将微观变化转化为宏观效应的超分子系统。这项工作证明了含偶氮苯聚合物（偶氮聚合物）和α-环糊精水溶液的渗透压的可逆光响应调制。渗透压测定表明，这种多价和光响应性的主客体复合物可用于调节溶液中溶质的浓度。在用紫外线和蓝光交替照射时，渗透压可逆地切换 28 mOsm kg ^–1. 开关幅度随着偶氮聚合物和环糊精的浓度线性增加。这种渗透压的剧烈变化是通过精心设计一种提供多价相互作用和高水溶性的偶氮聚合物来实现的。通过这种方式，我们的研究证明了通过超分子相互作用的光诱导调制对依数性质的可调控制。