ON THE WETTABILITY OF POLY(2-HYDROXYETHYLMETHACRYLATE)

The water wettability of dip coated poly(2-hydroxyethylmethacrylate) (PHEMA) films was measured by the sessile drop, captive bubble, and Wilhelmy plate techniques. In order to test specific effects arising from the amphipathic nature of PHEMA, the results were compared with those obtained from measurements on the comparatively hydrophobic poly(methylmethacrylate) (PMMA) and the hydrophilic poly(acrylic acid) (PAA). PHEMA showed a large contact angle hysteresis when measured by the sessile drop technique and was completely hydrated in underwater measurements. In the Wilhelmy plate technique, sequential scanning loops showed effects arising from hydration and, when the stage speed was increased, a peculiar sawtooth appearance, interpreted in the light of the dynamic behavior of PHEMA surfaces. © 1992.