Plasma coating of carbon nanofibers for enhanced dispersion and interfacial bonding in polymer composites

Abstract

Ultrathin films of polystyrene were deposited on the surfaces of carbon nanofibers using a plasmapolymerizationtreatment. A small percent by weight of these surface-coated nanofibers were incorporated into polystyrene to form a polymernanocomposite. The plasma coating greatly enhanced the dispersion of the nanofibers in the polymer matrix. High-resolution transmission-electron-microscopy (HRTEM)images revealed an extremely thin film of the polymer layer (∼3 nm) at the interface between the nanofiber and matrix. Tensile test results showed considerably increased strength in the coated nanofiber composite while an adverse effect was observed in the uncoated composites; the former exhibited shear yielding due to enhanced interfacial bonding while the latter fractured in a brittle fashion.