Dresden 2009 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 6: Thin Films

CPP 6.8: Talk

Monday, March 23, 2009, 16:00–16:15, ZEU 160

Thermoresponsive PNIPAM Microgel Films — •Anna Burmistrova, Matthias Karg, Martin Medebach, and Regine von Klitzing — Stranski-Laboratorium, Institut für Chemie, TU Berlin, Strasse des 17. Juni, 10623 Berlin

During the last decades microgels made of N-isopropylacrylamide (NIPAM) have attracted much interest and were studied by several techniques like microscopy and light scattering [1]. These polymer particles show thermoresponsive behaviour and can therefore be classified as "smart" materials. We synthesize monodisperse PNIPAM microgel with different contents of acrylic acid (AAc) to receive thermosensitive as well as pH-sensitive particles [2.3]. The films were prepared by spin coating and dip coating methods. Characterisation has been done using Atomic Force Microscopy (AFM) and ellipsometry. While AFM allows obtaining information about the particle size and arrangement [4], ellipsometry focuses on the overall film thickness [4]. In order to study the films under various conditions such as temperature and solvent composition we used liquid cells which allowed studying the surfaces against solution. The results show that the way of preparation and external stimuli like pH, ionic strength and temperature influences strongly the film structure. The internal correlation length was measured by SANS. [1] K. Kratz, T. Hellweg, W. Eimer, Polymer (2001) 42, 6531. [2] S. Höfl, l. Zitzler, T. Hellweg, S. Herminghaus, F. Mugele, Polymer (2007) 48, 245. [3] S. Nayak, L.A. Lyon, Angew. Chem. (2005) 117, 7862. [4] S. Schmidt, H. Motschmann, T. Hellweg, R. v. Klitzing, Polymer (2008) 49, 749.