Magnetic and optical properties of poly(diacetylene) block copoly (ether-urethanes) containing nitroxyl spin-labels in tfee main chain

Summary form only given. Segmented block-co-poly(ether-urethane-diacetylenes) of the general formula: where X = -(CH2)6-, have been prepared, characterized, and polymerized. Conceptually, such macromonomers have been designed to facilitate a combined probing of structural and electronic dynamics relevant to the poly(diacetylene) phase of the resulting 3D cross-linked composite. Thermally induced structural and electronic transformations in the UV- or g-cross-linked composites have been investigated by DSC and optical methods, while correlating the results with the spin probe dynamics data obtainable by parallel ESR measurements. It is shown that, besides being of significant help during studies of phase separation phenomena by DSC and optical methods, the ESR spin probe dynamics data add clarity to corresponding data for thermochromic transitions in these composites obtainable by FTIR, UV/VIS and NIR-FT- Raman. It is shown also that the presence of high concentrations of a spin probe in a block copolymer does not inhibit polymerization of DA-fragments in crystalline or para-crystalline domains, provided proper molecular design and phase segregation had been attained.