RELATIONSHIPS BETWEEN SURFACE WETTABILITY AND GLASS TEMPERATURES OF HIGH POLYMERS

The adhesion between a polymer and a solid substrate may be considered to be one type of complex liquid‐solid interaction. Relationships between surface wettability and bulk properties of liquidlike polymers are discussed. A new and direct empirical relationship between the glass temperature (Tg) and critical surface tension of a polymer (γc) is established: (Formula Presented.) where n = degree of freedom, defined by Hayes, Vm = molar volume, and Φ = interaction parameter, or the ratio between reversible work of adhesion and geometrical mean of the work of cohesion. The effect of polarity and hydrogen bonding on this relationship is also discussed. The calculated γc's are much closer to the observed values than those calculated on the basis of parachor. With this new wettability relationship the wettability of polymers, especially of those forming no hydrogen bonds, can be related to thermal, rheological, mechanical, and relaxational properties. Copyright © 1968 John Wiley & Sons, Inc.