Adhesion and friction behavior of positively or negatively patterned polymer surfaces measured by AFM

Abstract

Adhesion and friction behavior of the positively (micropillar) or negatively (microhole) patterned polydimethylsiloxane surfaces were comparatively investigated. The patterned surfaces were fabricated by replica molding technique and the surface morphologies of the patterned surfaces with different spacing between pillars/holes were characterized by atomic force microscope (AFM). The AFM with a colloidal probe was utilized to examine the adhesion and friction behavior of positively and negatively patterned surfaces. The results show that the positive patterning is more effective in reducing the adhesion than the negative patterning due to the smaller contact area between the positively patterned surfaces and colloidal probe. The friction of patterned surface was depended on the contact area between the contact pairs and the friction increments caused by the ‘collision effect’. The ‘collision effect’ is closely associated with the spacing between the pillars and the radius of the colloidal probe. The studied approach should be applicable to most patterned surfaces and open numerous opportunities for reducing the adhesive force and friction force between contact materials.