화학공학소재연구정보센터
International Journal of Heat and Mass Transfer, Vol.40, No.5, 1017-1033, 1997
Contact-Angle Temperature-Dependence for Water Droplets on Practical Aluminum Surfaces
zThis paper presents an experimental investigation of the temperature dependence of the quasistatic advancing contact angle of water on an aluminum surface polished in accordance with surface preparation techniques commonly employed in boiling heat transfer studies. The surface, speculated to contain aluminum oxide and organic residue left behind from the polishing process, was characterized with scanning electron microscopy, surface contact profilometry, and ellipsometry. By utilizing a pressure vessel to raise the liquid saturation temperature, contact angles were measured with the sessile drop technique for surface temperatures ranging from 25 to 170 degrees C and pressures from 101.3 to 827.4 kPa, Two distinct temperature-dependent regimes were observed. In the lower temperature regime, below 120 degrees C, a relatively constant contact angle of 90 degrees was observed. In the high temperature regime, above 120 degrees C, the contact angle decreased in a fairly linear manner. Empirical correlations were developed to describe this behavior which emulated previous experimental data for nonmetallic surfaces as well as theoretical trends.