Mechanotransduction in Polyelectrolyte Brushes - Towards Mechanically Addressable Smart Surfaces

拟议的项目重点关注的问题是，聚乙烯（PE）刷如何将机械变形转化为明确的化学信号（“机械转导”）。PE刷由一端接枝到表面的带电聚合物链组成。在计划的项目中，将调查变形PE刷的化学环境。已知强PE刷的垂直压缩可诱导固定化染料的解离，这可通过紫外-可见光谱法检测。这种方法将扩展到弱PE刷，其中压缩改变PE刷本身的解离程度。解离度将通过固定的pH指示剂定量。在第二步中，该方法将被应用到PE刷上的横向可拉伸的支持，其中接枝密度是通过机械变形改变。光学测量将补充由弱PE刷的解离度的电化学检测柔性金条。一个更探索性的部分工作的目的是在创建的光学应变传感器，利用变形后的共离子分布在刷的变化。计划的一组实验将提供详细的洞察变形下的PE刷的内部属性，并形成机械敏感表面和仿生应变传感器的发展的基础。

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.