Cold and pressure denaturation in a spherically symmetric water model.

PHYS 310

Sergey V. Buldyrev, buldyrev@yu.edu, Department of Physics, Yeshiva University, 500 W 185th Street, New York, NY 10033
We examine the behavior of a bead-on-a-string hard sphere polymer in molecular dynamics simulation in a solvent whose particles interact via the Jagla potential, a spherically symmetric ramp potential with two characteristic lengths: an impenetrable hard core and a penetrable soft core. The Jagla fluid has been recently shown to possess water-like structural, dynamic, and thermodynamic anomalies. We find that Jagla model also exhibits water-like solvation properties. The polymer dissolved in the Jagla liquid exhibits swelling upon both cooling and heating at fixed pressure or upon pressurizing at fixed temperature. This behavior resembles protein denaturation. The swelling at low temperatures happens as a first-order like phase transition associated with complete dewetting of the collapsed polymer globule. The thermodynamics of the swelling transition is compared with the predictions of the theory of hydrophobicity at large scales.
 

PHYS Poster Session - Water Mediated Interactions
7:30 PM-10:00 PM, Wednesday, August 20, 2008 Pennsylvania Convention Center -- Hall C, Poster

Division of Physical Chemistry

The 236th ACS National Meeting, Philadelphia, PA, August 17-21, 2008