A quantitative approach to study the interface of carbon nanotubes/elastomer nanocomposites. (May 2018) - Ning, Nanying
Graphical abstract: Highlights: PF-QNM technique was used to quantitatively characterize CNTs/NR interface. The interfacial thicknesses were got based on the Young's modulus' gradient change. The interfacial thickness of CNT/Si69/NR is much larger than that of CNTs/NR. The mechanical properties results were consistent well with the AFM results. Abstract: The interface between nanofillers and elastomers is one of the most important factors to determine the performance of elastomer nanocomposites. In this study, for the first time, we developed a method to quantitatively characterize the interfacial layer thickness of carbon nanotubes (CNTs)/Natural rubber (NR) composites by using peak force quantitative nanomechanical mapping (PF-QNM) technique of atomic force microscopy (AFM). We obtained the modulus and adhesion distribution of the composites, and selected those CNTs close to the sample surface, where the CNTs show lower adhesion for the accurate characterization of the interfacial thickness. Then, we characterized the thickness of interfacial layer according to the gradient change in Young's modulus. The results show that the average interfacial thickness of CNTs/NR composites is about 9 nm, similar with that in carbon black (CB)/elastomer composite (10 nm) reported in previous study, indicating the good interfacial interaction between CNTs and NR matrix. The average interfacial thickness of the modified CNTs/NR composites is about 17.4 nm, indicating the stronger interfacial interaction. The "Payne effect" and mechanical properties of these nanocomposites were also examined, and the results were consistent well with the AFM PF-QNM results. This study provides a new method to quantitative characterize the interface between filler and elastomer matrix at nanoscale resolution.