Nanomechanical and surface frictional characteristics of a copolymer based on benzoyl-1,4-phenylene and 1,3-phenylene

Surface mechanical and tribological properties of a copolymer based on benzoyl-1,4-phenylene and 1,3-phenylene were evaluated using nanoprobe investigation techniques and compared to the properties obtained at the macroscale. These copolymers are commonly referred to as self-reinforced polymers (SRPs) because of their intrinsic high strength and modulus without addition of a reinforcing agent. Specimens were prepared by spin casting, solvent casting, and compression molding. Surface mechanical properties and film thickness were measured by nanoindentation and scratching techniques. Friction properties were found using lateral force microscopy (LFM), and surface topography was imaged by tapping mode atomic force microscopy (AFM). Macroscale friction testing revealed a kinetic coefficient of friction of 0.08 for SRP, approaching that of Teflon. Similarly low relative friction coefficients were obtained in nanoprobe measurements. Nanoindentation of SRP, polycarbonate (PC), and polyetherimide (PEI) demonstrated superior surface hardness and modulus of SRP copolymer thin films.