Transmission electron microscopy of saturated hydrocarbon block copolymers

Abstract

Abstract Contrast for transmission electron microscopy (TEM) of microphase‐separated saturated hydrocarbon diblock copolymers has been obtained using ruthenium tetroxide (RuO 4 ). This technique exploits differences in the rate of transport of the oxidizing stain in rubbery amorphous versus semicrystalline, or glassy, microdomains. Rapid quenching from above the melting ( T m ), or glass transition ( T g ) temperature is shown to preserve the equilibrium melt morphology in poly(ethylene)‐poly(ethyl‐ethylene) (PE‐PEE), poly(ethylene)‐poly(ethylene‐propylene) (PE‐PEP), and poly(vinylcyclohexane)‐poly(ethyl‐ethylene) (PVCH‐PEE) diblock copolymers; PE melts at 108°C, PVCH is glassy up to about 140°C, while PEE and PEP remain rubbery down to approximately‐20°C and −56°C, respectively. Treatment of ultrathin sections of the quenched specimens with RuO 4 vapor led to welldefined TEM images, that revealed microdomain type and order. These results are consistent with SANS data taken under equilibrium conditions. © 1995 John Wiley & Sons, Inc.