Polydiacetylene copolymers

Owing to the special principles of topochemical reactions polydiacetylene copolymers can only be obtained if the comonomers form mixed crystals. Apart from this obvious preparative aspect mixed crystals are of interest because it can be expected that the monomer reactivity and the polymer properties can be effectively varied by the crystal composition. Similar effects have been successfully demonstrated in the isostructural doping of organic charge-transfer crystals In addition, it can be... 

Some of the copolymers composed of diacetylene should be mentioned, even though they may not fit exactly the definition of polydiacetylenes. 

Mostly Polyfluorenes Polysilanes Polydiacetylenes, Poly(p-Phenyleneethynylene)s and Copolymers... 

The approach that was adopted [66-69] was to prepare a series of urethane-diacetylene copolymers in which polydiacetylene units are incorporated into segmented copolyurethanes. It was shown in Section 8.1.1 that large strain-induced Raman band shifts can be obtained during the deformation of polydiacetylene single crystal fibers [8-12]. In fact, it is found that the largest shift measured so far (—20cm"V% strain) is for the C=C triple bond stretching band of polydiacetylenes (Table 8.1). 

Polydiacetylene LB films showed a conductivity of 10 S/cm after iodine doping [323,324] or ion irradiation [325], and polyacene-type ladder polymer can be formed by the irradiation of an electron beam or excimer laser [182,326]. The polyacetylene-type LB films were prepared using a diblock copolymer (Figure 14.44). The precursor block of the LB films could be converted to tra 5-polyacetylene by heat treatment, and the film showed a conductivity value of 2 x 10 S/cm after iodine doping [305]. LB films of carotene derivatives have also been reported [129,327,328]. 

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