Desolvation of polymers by ultrafast heating: Influence of hydrophilicity

Abstract

Using molecular-dynamics simulation, we investigate the consequences of ultrafast laser-induced heating of a small water droplet containing a solvated polymer. Two polymers are studied: polyethylene as an example of a hydrophobic, and polyketone as an example of a hydrophilic polymer. In both cases, when the droplet is heated below the critical temperature of water, strong water evaporation is started, but the polymer remains in contact with a central water cluster. However, upon heating beyond the critical temperature, the hydrophilic polyethylene becomes completely desolvated, while polyketone still remains solvated. We analyze this behavior in terms of the intermolecular interactions and of the expansion dynamics of the heated droplet.