TRIBOLOGICAL STUDY AND FINITE ELEMENT MODELLING OF SURFACE TEXTURES ON SU-8 AND PDMS POLYMER SURFACES

Abstract

THIS RESEARCH PROJECT FOCUSES ON THE TRIBOLOGICAL CHARACTERISTICS OF SUBSTRATES WITH PATTERNED SURFACES, NAMELY, FINGERPRINT PATTERNS THAT HAVE ROUNDED CORNERS ON SU-8 AND POLYDIMETHYLSILOXANE (PDMS). THE PROTUBERANCES (POSITIVE ASPERITY) ON THE SURFACE CAN LEAD TO A SIGNIFICANT REDUCTION IN FRICTION AND WEAR WHEN COMPARED TO FLAT FEATURELESS POLYMER SURFACES. DIFFERENT SURFACE PATTERNS WITH POSITIVE ASPERITIES (FINGERPRINT AND MICRO-DOT PATTERNS) AND NEGATIVE ASPERITIES (HONEYCOMB PATTERN) WERE ALSO INVESTIGATED FOR THEIR TRIBOLOGICAL BEHAVIORS. AMONG THE DIFFERENT SURFACE PATTERNS ON SU-8, THE NEGATIVE FINGERPRINT PATTERN EXHIBITED THE BEST TRIBOLOGICAL BEHAVIORS. THE FRICTION AND WEAR BEHAVIORS WERE AFFECTED BY CHANGES IN CONTACT AREA AND SPATIAL TEXTURE DENSITY THAT IS RELATED TO MULTIPLE ASPERITIES. AIMING TO FURTHER REDUCE FRICTION AND TO ENHANCE WEAR DURABILITY ON THE SU-8 TEXTURED SURFACES, PERFLUOROPOLYETHER (PFPE) WAS OVERCOATED AND IT SERVED AS AN EFFECTIVE PROTECTIVE LAYER