Ice Nucleation Activity of Polyvinyl Alcohol/Polyvinyl Acetate Polymer Solutions

Heidi L. Busse, Anjali Baikerikar, MIRIAM FREEDMAN, The Pennsylvania State University

     Abstract Number: 378
     Working Group: Aerosols, Clouds and Climate

Abstract
In the environment, some organisms have evolved the ability to either 1) promote the nucleation of ice or 2) inhibit ice growth. The proteins that have evolved to carry out these tasks are in some cases quite similar, in that they both have uniformly spaced hydroxyl groups that can either template water molecules to form ice or bind to ice directly to inhibit its growth. The polymer poly(vinyl alcohol) (PVA) has been used as a synthetic model of these proteins, and it displays both ice nucleation promoting and ice growth inhibiting properties, depending on its molecular weight and concentration. In this study, we have synthesized PVA from poly(vinyl acetate) (PVAc) with different degrees of hydrolysis and different arrangements of the monomers. For these polymers, we observe that ice nucleation activity increases with concentration until a certain concentration is reached and then ice nucleation activity decreases with temperature. We relate these results to the crossover concentration, viscosity, solubility, molecular weight, and molecular structure of the polymers. Such studies of synthetic models can provide insight into the promotion of ice nucleation and inhibition of ice growth of biological macromolecules like proteins.