Study of Polymer Interfacial Entanglements and Adhesion by High-Resolution Scanning Electron Microscopy

High-resolution scanning electron microscopy with low acceleration voltage was performed for the investigation of entanglements at interfaces of glassy polymers. Polymer interfaces failed via chain pull-out produced a large number of nano-sized fibrils. We discussed the correlation between the nano-scale features of the fracture surfaces and interfacial entanglements for three different interfaces. The interfaces between polymethylmethacrylate and poly(styrene-acrylonitrile) random copolymer (PMMA/SAN), between identical polystyrene homopolymers (PS/PS), and between PS/PMMA interfaces reinforced with block copolymers were investigated. we found that the "nano-fibrils" produced during the fracture reflected the local entaglement structures formed at narrow interfaces comparable to the entaglement spacing.