(581c) Confinement of Elastomeric Block Copolymers Via Forced Assembly

Forced-assembly processing provides a unique opportunity to study the effects of confinement via conventional melt processing co-extrusion techniques. In this research, an elastomeric triblock copolymer was confined via co-extrusion between alternating layers of a glassy material, such as polystyrene (PS). The microlayering process was utilized to produce novel materials with enhanced mechanical properties through selective manipulation of layer thicknesses and volume compositions. It was anticipated that confinement of the self-assembly process of block copolymers (BCP) would drastically affect the mechanical properties that could be achieved within multilayered thin films. Multilayer films consisting of an elastomeric, block copolymer confined between rigid PS layers were produced with layer thickness ranging from 10 nm to 600 nm. The layer uniformity and integrity of the multilayer systems have been analyzed through AFM for a 257 layer system. The co-extruded films showed a change in lamellar morphology of the bulk material as the block copolymer was confined by a glassy polymer. Preliminary thermo/mechanical data showed an increase in ductility as the block copolymer layer thickness decreases with the mode of deformation changing from crazing to shear yielding.