Mar 19, 2009
Bulletin of the American Physical Society
for an Invited Paper for the MAR09 Meeting of The American Physical Society Equilibrium features in the arrested phase separation of PNiPAM microgels VERONIQUE TRAPPE, Dept. of Physics, University of Fribourg, Switzerland We investigate the arrested phase separation of poly-N-isopropylacrylamide (PNiPAM) microgels. At large enough concentrations we observe the formation of a macroscopic gel-body that exhibits a peculiar temperature dependence. In a temperature-range, where the volume of the individual particles no longer changes, the final dimension of the macroscopic gel body depends on the depth of the quench into the phase separation regime. Increasing the quench depth results in a decrease of the dimension of the gel-body; this is reminiscent of a thermodynamically driven phenomenon and contrasts with the fact that the formation of the gel-bodies is due to the arrest of a phase separation process.