Urethane-substituted diacetylenes

We have attempted crystal growth of assorted diacetylenes by both liquid and vapor phase techniques. Urethane substituted diacetylenes are of particular interest because they are melt-stable and radiation polymerizable. Moreover, the polymer of the bis-ethylurethane of 5,7- dodecadiyn -1,12- diol (ETCD) exhibits the low energy ("excitonic") absorption peak found in the L-B PDA acid multilayer above and in poly-PTS, but is found in poly-TCDU at higher energy (32). Hence, we hoped to assess the role of this low energy absorption in nonlinear optical phenomena. 

The urethane-substituted polydiacetylenes exhibit thermo-chromic transition with low and high temperature crystal phases favoring acetylenic and butatriene backbone, respectively (4-6). Our interest in the application of epitaxial polymerization to diacetylenes has been the possibility of substrate control over orientation, structure, and the single crystal nature of thin films. 

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