INTERACTIONS BETWEEN HETEROGENEOUS SURFACES OF POLYMERS AND WATER

Preliminary investigations for the interactions between surfaces of po lymers and water were conducted by the measurements of contact (theta) and sliding-angles (alpha) with water. Work of adhesion (W) and inter action energies were subsequently calculated by using the Values of th eta and alpha, respectively. For the evaluation of actual performances of polymeric materials, shear strength of ice adhesion and snow accre tion were measured. Characteristics of homogeneous surfaces of polymer s in the interaction with water were obtained. On the basis of these c oncepts, the materials with heterogeneous surfaces were synthesized. R esults of surface characterizations in these polymers showed that the relationships between theta and alpha, and the other surface attribute s are very different according to polymer systems. The surface control led energetically and morphologically, and the superior hydrophobic pr operty prevented the snow accretion, but not ice adhesion. On the othe r hand, the organopolysiloxane modified with lithium compound provided the lowest strength of ice adhesion, but a poor capability of snow re pellency. In the structural and energetic viewpoints', interactions be tween heterogeneous surfaces and water (snow and ice) were discussed. For the theoretical prediction, the intermolecular energies between mo del polymers and water were calculated by using a molecular orbital SC F method. The order of interactions calculated were coincident with ex perimental values deduced from alpha, but not from theta. The advantag e of heterogeneity of surface was supported by the theoretical underst anding. (C) 1994 John Wiley and Sons, Inc.