Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 16: Interfaces and Thin Films II (joint session with DECHEMA and VDI)
CPP 16.3: Vortrag
Dienstag, 12. März 2013, 10:15–10:30, H40
Internal structure and dynamics of microgel films at solid interfaces — •Stefan Wellert1, Yvonne Hertle2, Marcel Richter1, Peter Müller-Buschbaum3, Thomas Hellweg2, and Regine von Klitzing1 — 1Stranski Laboratorium, Inst.f. Chemie, TU Berlin, 10623 Berlin — 2Fakultät f. Chemie, Physikalische Chemie III, Universität Bielefeld, 33615 Bielefeld — 3Physikdepartment E13, TU München, 85747 Garching
The physico-chemical properties of stimuli-responsive polymers attract great interest in basic research and lead to a lively discussion of potential technical applications. A prominent example are microgel systems, which undergo a temperature induced phase transition corresponding to a discontinuous shrinking with increasing sample temperature. Microgel particles can be organized as ultra-thin films at solid surfaces, e.g. silicon single crystal surfaces. This leads to changes in the shrinking behaviour and the LCST. For example, the LCST is reduced between 1°C and several °C with respect to the bulk phase. These findings raise the question how the interactions with the solid surface affect the internal structure and dynamics of the microgel particles. In a series of surface sensitive scattering experiments we addressed this question mainly focussing on the correlation length in the polymer network. Here, we present GISANS measurements investigating a microgel containing the monomer NIPAM, cross-linked with BIS (2 mol-% with respect to the mass of NIPAM). Additionally, first measurements addressing the internal dynamics in this system using neutron spin-echo spectroscopy under grazing incidence (GINSE) are discussed.