Polymer, Vol.39, No.15, 3321-3326, 1998
Crystal thicknesses in semicrystalline oxyethylene/oxybutylene block copolymers by atomic force microscopy and SAXS
The structure of thin crystallized films of a diblock or a triblock copolymer deposited on silicon has been investigated using atomic force microscopy (AFM). Non-contact mode AFM was used to investigate the topography of crystallites of poly(oxyethylene)/poly(oxybutylene) (E/B) block copolymers at room temperature, where E is crystallized and B is amorphous. The crystal thicknesses determined from AFM were compared to bulk layer spacings determined using small-angle X-ray scattering (SAXS). This technique showed that E41B22E41 (the subscript denotes the number of repeat units) largely crystallized in a monolayer with unfolded E blocks at the substrate and folded (looped) B blocks at the polymer-air interface, and with the E blocks tilted at an angle of ca. 60 degrees relative to the substrate plane. Multiple layers with a common step height were observed for the diblock E27B6 crystallites, which were largely comprised of unfolded chains, also with E block tilted at an angle of ca 60 degrees with respect to the substrate plane.