Mechanotransduction in Polyelectrolyte Brushes - Towards Mechanically Addressable Smart Surfaces

• Applicant: Dr. Johanna Bünsow
• Subject Area: Experimental and Theoretical Physics of Polymers
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 158439160

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.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Dr. Wilhelm Huck