Lattice Bending in Poly(Diacetylene) Droplets Near Surfaces

Abstract

ABSTRACTDroplets of l, 6-di(N-carbazolyl)-2, 4 hexadiyne (DCHD) diacetylene were prepared by room temperature evaporation of dilute (0.01 wt %) solution of the monomer in chloroform on amorphous carbon-coated mica substrates. HREM and SAED examination revealed small crystallographically textured droplets (∼1 μm diameter) with cracks parallel to the [001] chain direction. The droplet geometry allowed us to investigate the structure of the polymer near edges both parallel and perpendicular to the chain axis. It was found that the curvature of the droplet edge caused a local bending of the polymer crystal lattice. The direct imaging of the molecular organization near the droplet surface allowed an investigation of the mechanisms of lattice bending via the formation of edge dislocations. An understanding of these defects is important in determining how they relate to the optical properties of poly(diacetylenes).