Microtribological Properties of Topographically-modified Polymeric Surfaces with Different Pitches

Abstract

Topographically-modified poly (methyl-methacrylate) (PMMA) surfaces with sub-micron pillars were investigated for their tribological properties at a micro-scale. The topographical modification was done by using capillarity-assisted force lithography, in which a patterned elastomeric mold was placed on the polymer film spin-coated on a silicon wafer; a negative replica of the mold was then formed by raising the temperature well above the glass-transition temperature of the polymer. Various patterns were fabricated with different pitches. The modified surfaces were examined for their micro-tribological properties in comparison with those of the flat polymer film for various pitch values by using a micro-tribotester. An atomic force microscope (AFM) was used to study the worn surfaces of the modified surfaces and the polymer film after the tests. Results indicated that the topographical modification was effective in reducing the friction of the polymeric surface. Further, among the topographically-modified surfaces, the pitch significantly affected their tribological behavior. We proposed that topographical modification is an effective method for enhancing the tribological properties of polymeric surfaces on a small scale.