A block copolymer nanotemplate for mechanically tunable polarized emission from a conjugated polymer

A polymer blend system consisting of polystyrene grafted onto poly(p-phenylene ethynylene) (PS-g-PPE) and poly(styrene-block-isoprene-block-styrene) triblock copolymer (SIS) yields highly polarized emission due to the unidirectional alignment of the PPE mols. During the roll casting, the triblock copolymer microphase separates and creates unidirectionally aligned PS cylindrical microdomains in the rubbery PI matrix. PPE, a fluorescent conjugated polymer, was grafted with polystyrene (PS) side chains that enabled sequestration and alignment of these rigid backbone emitter mols. into the PS microdomains of the SIS triblock copolymer. Deforming the thermoplastic elastomer in a direction perpendicular to the orientation direction of the cylinders causes rotation of the PS cylinders and the PPE emitter mols. and affords tunable polarized emission due to reorientation of the PPE contg. PS cylinders as well as film thinning from Poisson effect. [on SciFinder(R)]