PRECISE MEASUREMENT OF THE SURFACE SHEAR VISCOSITY OF 1-OCTADECANOL MONOLAYERS AT THE WATER-SURFACE AND THE KINETIC-ENERGY EFFECT OF FLOW OF MONOLAYERS

A microcomputer-controlled instrument for measuring precise surface shear viscosity of monolayers at the air/water interface by the canal method was constructed. The surface shear viscosity of 1-octadecanol monolayers on water surface at 20-degrees-C was measured with this instrument using 22 kinds of canals of various length and width. It was observed that 1-octadecanol monolayers in the liquid-condensed state obeyed Newtonian flow as a whole but the viscosity increased considerably with decreasing length and increasing width of the canal. This is caused by the kinetic energy effect of the flow of monolayers, which has not been reported in two-dimensional flow. The surface shear viscosity of 1-octadecanol monolayers obtained by the flow from 10 mN/m to 5 mN/m at 20-degrees-C was 2.25 +/- 0.10-mu-Pa.s.m in average.