AbstractIntroducing photo‐responsive molecules offers an attractive approach for remote and selective control and dynamic manipulation of material properties. However, it remains highly challenging how to use a minimal amount of photo‐responsive units to optically modulate materials that are inherently inert to light irradiation. Here we show the application of a light‐driven rotary molecular motor as a “motorized photo‐modulator” to endow a typical H‐bond‐based gel system with the ability to respond to light irradiation and create a reversible sol‐gel transition. The key molecular design feature is the introduction of a minimal amount (2 mol %) of molecular motors into the supramolecular network as photo‐switchable non‐covalent crosslinkers. Advantage is taken of the subtle interplay of the large geometry change during photo‐isomerization of the molecular motor guest and the dynamic nature of a supramolecular gel host system. As a result, a tiny amount of molecular motors is enough to switch the mechanical modulus of the entire supramolecular systems. This study proves the concept of designing photo‐responsive materials with minimum use of non‐covalent light‐absorbing units.
摘要引入光响应分子为远程选择性控制和动态操纵材料特性提供了一种极具吸引力的方法。然而,如何使用极少量的光响应单元对本身对光惰性的材料进行光学调制,仍然是一个极具挑战性的问题。在这里,我们展示了如何应用光驱动旋转分子马达作为 "机动光调制器",赋予典型的基于 H 键的凝胶体系对光照射做出响应的能力,并创造出可逆的溶胶-凝胶转变。关键的分子设计特征是在超分子网络中引入极少量(2 摩尔%)的分子马达作为光开关非共价交联剂。我们利用了分子马达客体在光异构化过程中发生的巨大几何形状变化与超分子凝胶宿主系统的动态性质之间的微妙相互作用。因此,极少量的分子马达就足以改变整个超分子系统的机械模量。这项研究证明了用最少的非共价吸光单元设计光响应材料的概念。