Molecular and Crystal Engineering of Polydiacetylenes: Modification of Optical Properties.
Technical rept. no. 5
LOWELL UNIV MA DEPT OF CHEMISTRY
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Polydiacetylenes have attracted a great deal of attention over the past decade due to their interesting electronic and optical properties. It is also one of few classes of polymeric materials that can be produced in the form of macroscopic single crystals. These polymeric crystals are characterized by a tremendous richness of structure. A large number of side groups may be grafted onto the polymeric backbone stem which has a planar extended chain unsaturated structure. The many different side groups R and R that can be part of the monomer structure have a strong influence on the crystalline organization and polymerization behavior in the solid state. Depending upon the chemical nature of the side groups a number of crystalline phases may be present with different conformation of the side groups. Whether solid state polymerization in a particular crystalline phase will occur is dictated by the intermolecular spacings and precise arrangement of the adjacent diacetylene functionalities. Crystallograpy.