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Session L36 - General Poster Session II.
POSTER session, Wednesday morning, March 22
Exhibit Hall, MCC

[L36.030] Depletion and Reentrant Phase-transitions with Colloids and Dendrimers

A. G. Yodh, Jian Zhang, Subrata Sanyal (Department of Physics amp; Astronomy, University of Pennsylvania, PA 19104)

Starburst Polyamidoamine (PAMAM) dendrimers represent ``dense star'' polymers that unlike classical polymers have specific size and shape characteristics, a high degree of monodispersity and molecular uniformity. Using optical microscopy, we have studied systems composed of aqueous suspensions of charged polystyrene colloids and ``generation'' 9.5 PAMAM dendrimers. Depletion-mediated crystallization of colloids is observed. In addition, an entropy-driven reentrant phase behavior (liquidlike to solidlike to liquidlike) of colloids is tentatively observed with the systematic increase of dendrimer concentration and a fixed colloid concentration.

Part L of program listing