DYNAMIC WETTING AND DEWETTING OF A LOW-ENERGY SURFACE BY PURE LIQUIDS

A high resolution optical method was used to acquire contact angle-vel ocity data for hexadecane and octamethylcyclotetrasiloxane (OMCTS) adv ancing and receding on a smooth, virtually homogeneous fluorinated sur face. The predictive abilities of the hydrodynamic, molecular-kinetic and combined molecular-hydrodynamic models of wetting dynamics were co mpared. In this context the behavior of hexadecane and OMCTS were dist inctly different. Where application of the molecular-kinetic model is most appropriate (hexadecane advancing) the motion of the contact Line does agree well with the molecular length. However when hydrodynamics play a role and the combined molecular-hydrodynamic model is required , then the characteristic lengths obtained greatly exceed molecular di mensions.