Regensburg 2010 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 4: Focus: Structure and Dynamics of Responsive Hydrogels II

CPP 4.3: Talk

Monday, March 22, 2010, 14:45–15:00, H37

Thermodynamics of aqueous solutions containing N-isopropyl acrylamide hydrogels — •Viktor Ermatchkov, Luciana Ninni Schäfer, and Gerd Maurer — Laboratory of Engineering Thermodynamics (LTD), Department of Mechanical and Process Engineering, University of Kaiserslautern, D-67653 Kaiserslautern, Germany

Applications of hydrogels are based on their physico-chemical properties, among which the swelling behavior is one of the most important. The development of models for a reliable description of the phase equilibrium in systems containing hydrogels requires quantitative experimental data on the swelling behavior of well-characterized hydrogels.

In previous work, the phase equilibrium and swelling properties of some synthetic hydrogels was determined and quantitatively described by combining expressions for the Gibbs energy of an aqueous solution of polymers and for the Helmholtz energy of an elastic network. The hydrogels consisted of a single nonionic monomer N-isopropyl acrylamide (NIPAAm) as well as of mixtures of NIPAAm and anionic comonomer (sodium methacrylate). In the current work these investigations are extended to other (NIPAAm)-hydrogels, in particular to hydrogels with two ionic comonomers of different charges (2-Acryloylamino-2-methylpropane-1-sulfonic acid and N-[3-(dimethylamino)propyl]-2-methylprop-2-enamide) and to hydrogels containing also a zwitterionic comonomer (3-(dimethyl{3-[(2-methylacryloyl)amino]propyl}ammonio)propane-1-sulfonate).

New experimental results for the swelling of such hydrogels in aqueous solutions as well as model extensions are presented.