On the spreading of glycerol trioleate

Spreading of liquids can often successfully be described by either hydrodyn amic or molecular kinetics theories. The natural wetting of small, sessile drops of glycerol trioleate on smooth, Rat, solid surfaces may be expected to comply with the former model, yet nonnegligible differences are manifest , which apparently cannot be accounted for by the addition of a molecular k inetics term. We postulate that modifications to the spreading rate are due to an effect of time-dependent molecular orientation occurring after liqui d molecules have contacted the solid substrate. (C) 2001 Academic Press.