Spinodal dewetting of thin films

Abstract

Stable thin liquid films are of various scientific and technological applications, e.g., in optical coating, manufacturing photographic films, painting technologies, forming dielectric layers, coating thin wires and fibers, lubricants, adhesives, etc. Generally these films are used to improve or modify the surface characteristics of a material and to protect it from the external atmosphere. However, the instabilities in a thin film may lead to rupture, hole formation, and other morphological changes which amplify the nonuniformity in the thin film [1]. This morphological evolution in an unstable thin film is generally known as ‘dewetting’ [2]. There have recently been a number of theoretical and experimental studies on dewetting in thin films [3-6]. The process of ‘spinodal dewetting’ comes into the category of a general class of phenomena, spinodal decomposition [7] for example, in which thermal fluctuations are amplified. There is a characteristic mode out of the modes of these amplified fluctuations, which grows fastest and dominate the emerging dewetting pattern. The pattern formation taking place during dewetting can also be of great importance in nanotechnology, with the possibility of designing patterned surfaces for specific applications, e.g., for preparing quantum dots [8], nanorings [9], etc.