Oriented array of polyethylene-block-poly(ethylene oxide) nanoplatelets in unsaturated polyesters cross-linked coatings

Transparent coatings of cross-linked unsaturated polyester (UP) containing staggered platelets of polyethylene-block-poly(ethylene oxide) with their normal perpendicular to the substrate have been readily prepared by a solvent assisted spin-coating method. For this purpose, homogeneous liquid dispersions of block copolymer platelets in liquid UP resin have been prepared using a selective solvent, deposited onto flat substrates by spin-coating and converted into a transparent solid layer by photochemical cross-linking. Although such stratified morphology has been already reported for inorganic nanoplatelets (typically clay particles), we report for the fist time the formation of such stratified morphology in fully organic system. The shear-induced origin of this organization has been confirmed by the rheological properties of the uncured systems where a pronounced non-Newtonian behavior has been observed.