Regensburg 2007 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: POSTER: Colloids and Nanoparticles

CPP 9.16: Poster

Montag, 26. März 2007, 16:00–18:00, Poster B

Influence of Temperature, pH and Ionic Strength on the Swelling-Behavior of New Poly(N-isopropylacrylamide-co-allylacetic acid) Microgels — •Matthias Karg and Thomas Hellweg — TU Berlin, Stranski-Laboratorium für Physikalische und Theoretische Chemie, Strasse des 17. Juni 124, D-10623 Berlin, Germany

The volume phase transition of colloidal microgels made of N-isopropylacrylamide (NIPAM) is well-studied and it is known that the transition temperature can be affected by copolymerization. A series of poly(N-isopropylacrylamide-co-allylacetic acid) copolymers with different contents of allylacetic acid (AAA) has been prepared using simple surfactant-free emulsion polymerizations. The thermoresponsive behavior of these partciles was studied by means of dynamic light scattering (DLS). Further characterization was done employing atomic force microscopy (AFM), transmission electron microscopy (TEM) and zeta potential-measurements. While the TEM and AFM observations manifest the spherical shape and low polydispersities of the copolymers, the zeta potential measurements provide information about the relative surface charge.
Since these copolymers are much more sensitive to external stimuli such as pH and ionic strength than their pure PNIPAM counterparts the swelling behavior was investigated at two different pH values and different salt concentrations.