INTERACTIONS BETWEEN HETEROGENEOUS SURFACES OF POLYMERS AND WATER

Preliminary investigations for the interactions between surfaces of polymers and water were conducted by the measurements of contact (theta) and sliding-angles (alpha) with water. Work of adhesion (W) and interaction energies were subsequently calculated by using the Values of theta and alpha, respectively. For the evaluation of actual performances of polymeric materials, shear strength of ice adhesion and snow accretion were measured. Characteristics of homogeneous surfaces of polymers in the interaction with water were obtained. On the basis of these concepts, the materials with heterogeneous surfaces were synthesized. Results of surface characterizations in these polymers showed that the relationships between theta and alpha, and the other surface attributes are very different according to polymer systems. The surface controlled energetically and morphologically, and the superior hydrophobic property prevented the snow accretion, but not ice adhesion. On the other hand, the organopolysiloxane modified with lithium compound provided the lowest strength of ice adhesion, but a poor capability of snow repellency. In the structural and energetic viewpoints', interactions between heterogeneous surfaces and water (snow and ice) were discussed. For the theoretical prediction, the intermolecular energies between model polymers and water were calculated by using a molecular orbital SCF method. The order of interactions calculated were coincident with experimental values deduced from alpha, but not from theta. The advantage of heterogeneity of surface was supported by the theoretical understanding. (C) 1994 John Wiley and Sons, Inc.