Anisotropic Conductivity of Diblock Copolymer Films

The first part of this article reviews the orientation of the surface and the in-bulk microdomain structures of diblock copolymers. Well-defined poly(styrene-b-2-vinylpyridine) diblock copolymers (about 50 wt% polystyrene blocks) formed horizontally oriented lamellar microdomains when these copolymers were cast from a nonselective solvent by means of the air–copolymer and substrate–copolymer interactions. The second section reviews the preparation of semiconducting materials by the exposure of these films to alkyl dihalide vapor. This film had an anisotropic conductivity with about 8 orders of magnitude. The third section reviews the construction of ionic complex phases by an ion-exchange reaction of quaternized poly(2-vinylpyridine) (P2VP) layers with lithium perchlorate. Finally, the introduction of colloidal silver into quaternized P2VP layers by reduction of silver iodide is reported. High electrical anisotropy originated in the orientation of microphase-separated structure of diblock copolymer films.