Regensburg 2013 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 42: New Instruments and Methods
CPP 42.6: Talk
Thursday, March 14, 2013, 12:45–13:00, H39
Pseudo-critical behavior of the static and the dynamic expansion coefficient at the volume phase transition of PNIPAM solutions as seen by Temperature Modulated Optical Refractometry — •Ralitsa Aleksandrova1, Martine Philipp1,2, Ulrich Müller1, Roland Sanctuary1, Peter-Müller Buschbaum2, and Jan K. Krüger1 — 1Université du Luxembourg, LPM, Luxembourg, Luxembourg — 2TU München, Physik-Department, LS Funktionelle Materialien, Garching, Germany
The volume phase transitions of aqueous PNIPAM solutions are investigated by the novel technique of Temperature Modulated Optical Refractometry (TMOR) as a function of temperature and time. In addition to the refractive index, TMOR yields information about the static and dynamic thermo-optical coefficient and eventually the static and dynamic volume coefficient of thermal expansion [1]. The observed pseudo-critical behavior of these physical quantities evidences a rather direct coupling to the order parameter associated with the collapse of the polymer coils. A preliminary interpretation with regard to the involved structural changes on mesoscopic and macroscopic scales is given based on these findings.
[1] M. Philipp, U. Müller, R. Aleksandrova et al., Soft Matter 8, 11387 (2012)