Mechanotransduction in Polyelectrolyte Brushes - Towards Mechanically Addressable Smart Surfaces

拟议的项目重点研究聚电解质(PE)刷子如何将机械变形转化为明确的化学信号(“机械转导”)。PE刷子由带电的聚合物链组成，这些聚合物链的一端嫁接到表面。在计划的项目中，将对变形PE刷子中的化学环境进行调查。众所周知，强力PE刷子的垂直压缩可能会导致固定化染料的解离，这是UV-Vis光谱可以检测到的。这种方法将扩展到弱PE笔刷，其中压缩改变PE笔刷本身的解离程度。解离的程度将通过固定化的pH指示剂来量化。在第二步中，该方法将应用于横向可伸展支架上的PE刷子，其中接枝密度通过机械变形而改变。除了光学测量，还将对柔性金条上的弱PE刷子的离解程度进行电化学检测。这项工作的一个更具探索性的部分是创造光学应变传感器，这种传感器利用电刷中的共离子分布在变形时的变化。计划中的一系列实验将详细了解PE刷子在变形时的内部特性，并为开发机械敏感表面和仿生应变传感器奠定基础。

The proposed project focuses on the question how polyelectrolyte (PE) brushes can convert mechanical deformation into well-defined chemical signals (“mechanotransduction”). PE brushes consist of charged polymer chains which are grafted with one end to a surface. In the planned project, the chemical environment in deformed PE brushes will be investigated. It is known that the vertical compression of a strong PE brush may induce the dissociation of immobilised dyes which is detectable by UV-vis spectroscopy. This approach will be extended to weak PE brushes, where compression alters the degree of dissociation of the PE brush itself. The degree of dissociation will be quantified by immobilised pH indicators. In a second step, the method will be applied to PE brushes on laterally stretchable supports where the grafting density is changed by mechanical deformation. Optical measurements will be supplemented by an electrochemical detection of the degree of dissociation of weak PE brushes on flexible gold strips. A more explorative part of the work aims at the creation of optical strain sensors which exploit changes of the co-ion distribution in the brush upon deformation. The planned set of experiments will provide detailed insight into the interior properties of PE brushes under deformation and form a basis for the development of mechanosensitive surfaces and bio-mimetic strain sensors.