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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 35: Poster Session II
CPP 35.11: Poster
Wednesday, March 29, 2023, 11:00–13:00, P1
Diffusion, Thermodiffusion and turbidity of thermoresponsive Poly(N-acryloylglycinamide) in water. — •Roman Reh1, Nikola Majstorovic2, Seema Agarwal2, and Werner Köhler1 — 1Universität Bayreuth, Physikalisches Institut, Germany — 2Universität Bayreuth, Macromolecular Chemistry II, Germany
We report about measurements on Poly(N-acryloylglycinamide) (PNAGA) in aqueous solution. Diffusion-, Thermodiffusion- and Soretcoefficients were measured with the polymer in linear form and as a crosslinked microgel. Furthermore, temperature dependent measurements on turbidity were done with the linear polymer. Experiments on diffusion were performed with the Optical-Beam-Deflection technique where a vertical temperature gradient is applied to the sample and information about the time dependent distribution of temperature and concentration in the sample is gathered by recording the position of a laser beam, which traverses the sample and gets deflected. This is because the refractive index changes with temperature and concentration, which on its part changes due to thermodiffusion. Turbidity measurments show a UCST-behavior and a hysteresis in the temperature of the cloud point, depending on the direction of the temperature ramp, which is in accordance with results from literature. Thermodiffiusion- and Soretcoefficients at different temperatures are described with an exponential Piazza function [S. Iacopini et al., Eur. Phys. J. E 19, 59-67 (2006)] and are comparable for the linear polymer and the microgel, showing a systematical behaviour and a change in sign in the region of about 35 to 40 ∘C.