Evaluation of composite interfacial properties based on carbon fiber surface chemistry and topography: Nanometer-scale wetting analysis using molecular dynamics simulation

According to surface chemistry and topography of different high-modulus carbon fiber (HMCF), interfacial properties of various HMCF composite were evaluated, and nanoscale wetting analysis of HMCF were studied using experimental methods and molecular dynamics simulation. Hierarchical amount of active functional groups and nanoscale grooves were detected on the surface of pristine HMCF (p-HMCF), anodic oxidized HMCF (a-HMCF) and sized HMCF (s-HMCF). Remarkable enhancements in interfacial properties of a-HMCF and s-HMCF composites were obtained, which was ascribed to free-void interface from improved surface energy and wettability. Poor interfacial bonding of p-HMCF composites was due to generation of many nanobubbles with pinned contact lines during the wetting of the surface microgrooves with high aspect ratio and chemical inertness. Schematic of interfacial compatibility mechanisms was proposed to illustrate the correlation between surface features of carbon surface and interfacial properties of their composites.