Fluid viscosity is ubiquitous property and is of practical importance in intelligent fluids, industrial lubrication, and pipeline fluid transportation. Recently, there has been a surging interest in viscosity regulation. Here, we have developed a group of photorheological fluids by utilizing azobenzene polymers with a light-induced microstructure transformation. In this work, a photosensitive polymer with 4,4′-bis-hydroxyazobenzene as the main chain was designed and synthesized as a pivotal functional material. The sufficiently large structural difference under ultraviolet and near-infrared light makes it possible to regulate the viscosity of a polyethylene glycol solution. The viscosity of the photosensitive rheological fluids under ultraviolet light radiation is found to be up to 45.1% higher than that under near-infrared light radiation. To explore this intelligent lubricating technology, the friction regulation of ceramic sliding bearings was investigated utilizing photosensitive rheological fluids. Reversible friction regulation with a ratio of up to 3.77 has been achieved by the alternative irradiation of near-infrared and ultraviolet light, which can be attributed to the differences in mechanical properties and molecular structures under ultraviolet and near-infrared light according to both simulations and experiments. Such photorheological fluids will have promising applications in controllable lubrication, intelligent rheological fluids, and photosensitive dampers.

流体粘度是普遍存在的特性，在智能流体、工业润滑和管道流体输送中具有重要的实际意义。最近，人们对粘度调节的兴趣激增。在这里，我们利用具有光诱导微观结构转变的偶氮苯聚合物开发了一组光流变流体。在这项工作中，设计并合成了一种以 4,4'-双-羟基偶氮苯为主链的光敏聚合物作为关键功能材料。紫外光和近红外光下足够大的结构差异使得调节聚乙二醇溶液的粘度成为可能。发现紫外光辐射下光敏流变流体的粘度比近红外光辐射下高45.1%。为了探索这种智能润滑技术，利用光敏流变液研究了陶瓷滑动轴承的摩擦调节。通过近红外光和紫外光交替照射实现了比例高达3.77的可逆摩擦调节，这可以归因于根据模拟和近红外光下机械性能和分子结构的差异。实验。这种光变流体将在可控润滑、智能流变流体和光敏阻尼器中具有广阔的应用前景。77是通过近红外和紫外光交替照射实现的，这可以归因于根据模拟和实验在紫外和近红外光下机械性能和分子结构的差异。这种光变流体将在可控润滑、智能流变流体和光敏阻尼器中具有广阔的应用前景。77是通过近红外和紫外光交替照射实现的，这可以归因于根据模拟和实验在紫外和近红外光下机械性能和分子结构的差异。这种光变流体将在可控润滑、智能流变流体和光敏阻尼器中具有广阔的应用前景。