PUB - Publikationen an der Universität Bielefeld

The aim of this thesis was the development of smart, thermoresponsive surface coatings based on poly(*N*-isopropylacrylamide) (pNIPAM) microgels for applications in biological and medical research. In order to understand microgel behavior when deposited on a surface the physical properties and the morphology of adsorbed microgels had to be studied and understood.
Initial experiments using atomic force microscopy (AFM) aimed at the characterization of various microgels adsorbed and dried on a surface in order to gain knowledge about the influence of the microgel architecture on their behavior. Further experiments were conducted to examine the deposition behavior of microgels when deposited with standard coating procedures such as spin-coating, dip-coating and spray-coating. Results from these experiments were used to optimize these processes for the manufacturing of microgel monolayers. In the course of a BMBF funded project the obtained results were utilized to develop wound healing essays for medical applications in cooperation with the institutes Fraunhofer IZI, Fraunhofer IAT, the University Bayreuth and the companies Ibidi GmbH and PolyAn GmbH.
Results and insights gained from this cooperation led to the idea to develop transfereable thermoresponsive coatings. The principle idea was to cross-link the microgels in a monolayer in order to obtain a free-standing, thermoresponsive film which than can be deposited on various substrates and surfaces. In order to be able to cross-link the microgel the thermoresponsive monomer NIPAM was copolymerized with the monomer *N*-Benzhydrylacrylamide (NBHAM). The aromatic moieties of the monomer NBHAM enabled the possibility to cross-link the microgels in a monolayer using an electron beam. The cross-linked layer could than be detached from the initial substrate and transferred to any arbitrary substrate. Furthermore it is possible to use the free-standing microgel film as a temperature controllable membrane. In conductivity measurements it has been shown that the resistivity of the membrane can be tuned by changing the external temperature.