Atomic force microscopy (AFM) studies of sized carbon fibers

Atomic Force Microscopy (AFM) studies were conducted on two sets of carbon fibers that were prepared with varying concentrations of applied sizing. Both qualitative and quantitative data were obtained. Novel AFM scanning techniques were employed, as a means to better understand the carbon fiber-sizing interface.; The AFM results yield qualitative surface topographic information together with quantitative surface parameters such as average roughness (Ra), root mean square roughness (RMS), and excess surface area (XSSA). A correlation is found between these surface parameters and increases in the applied sizing concentration. Oscillating cantilever scan modes are found to resolve much smaller features at the nanometer-scale compared to constant force scan modes.; A variety of scan techniques are utilized in an attempt to differentiate the applied sizing from the neat fiber surface. These “physical contrast” scan modes include Lateral Force Microscopy (LFM), Modulated Force Microscopy, Phase Imaging, Scanning Kelvin Microscopy (SKM), and Differential Capacitance Microscopy. These modes provide a variety of information regarding the topographic features of the neat fibers as well as the sizing distribution on the fiber surface.