Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 21: POSTERS Colloids, Nanoparticles and Aggregates
CPP 21.20: Poster
Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A
Influence of temperature and pH on thermoresponsive PNIPAM films — •Anna Burmistrova1, Matthias Karg1, Thomas Hellweg2, and Regine von Klitzing1 — 1TU Berlin, Institut für Chemie, Stranski-Laboratorium, Str. d. 17. Juni 124, 10623 Berlin, Germany — 2Universität Bayreuth, Physikalische Chemie 2, Universitätsstr. 30, 95440 Bayreuth, Germany
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. These polymer particles show a thermoresponsive behaviour and can be classified as "smart" materials. By copolymerisation with organic acids such as acrylic acid (AAc) the temperature of the volume phase transition as well as the swelling ratio can be influenced. Moreover charged copolymers are more sensitive to changes in pH and ionic strength. Depending on the way of preparation one can achieve particles with rather low polydispersities which makes them more interesting for applications like surface coatings and sensor design. Characterisation of coated surfaces with poly-NIPAM-co-AAc microgels has been done using Atomic Force Microscopy (AFM) and ellipsometry. While AFM allows to obtain information about the particle size and arrangement, ellipsometry focuses on the overall film thickness. In order to study the films under various conditions such as temperature and solvent composition we employed liquid cells which allowed to study the surfaces under solution. The results show that the way of preparation and external stimuli like pH and temperature influences strongly the structure of the films.