Quantitative measurement of interdiffusion at polymer–polymer interfaces with TEM/EDS and EELS

Transmission electron microscopy and energy dispersive spectroscopy (TEM/EDS) were used to map the concentration profile at the interface of a poly(vinyl chloride) and poly(methyl methacrylate) bilayer. Thin sections in the order of 800 Å were cut using an ultramicrotome, examined with TEM, and the concentration profile was mapped with EDS. The intensity of fluorescene X‐rays was adjusted for sample thickness variation by measuring the relative thickness across the interface with electron energy‐loss spectroscopy (EELS). The interfacial thickness of the bilayer after 6 h at 120°C was 1.5 μm, whereas the interdiffusion coefficient was determined as 8.0 × 10−14 cm2/s.