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 co polymer deposited on silicon has been investigated using atomic force microscopy (AFM). Non-contact mode AFM was used to investigate the top ography of crystallites of poly(oxyethylene)/poly(oxybutylene) (E/B) b lock copolymers at room temperature, where E is crystallized and B is amorphous. The crystal thicknesses determined from AFM were compared t o bulk layer spacings determined using small-angle X-ray scattering (S AXS). This technique showed that E41B22E41 (the subscript denotes the number of repeat units) largely crystallized in a monolayer with unfol ded E blocks at the substrate and folded (looped) B blocks at the poly mer-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 w ere largely comprised of unfolded chains, also with E block tilted at an angle of ca 60 degrees with respect to the substrate plane. (C) 199 8 Elsevier Science Ltd. All rights reserved.