Diacetylenes film growth

The diacetylene monomer employed in the thin film growth technique pioneered by Langmuir and Blodgett (12) must have a strongly polar "head group" and a nonpolar-"tail." The monomer we have used in our studies, CH3 - (CH2)i5 - C = C - C = C -(CH2)g - COOH, has a long alkyl group as the nonpolar "tail."... 

Convincing evidence for phase separation was obtained from the photopolymerization behavior of 6 in the mixed 6/DSPE monolayer films. Photopolymerization of diacetylenes is a topotactic process which requires the proper alignment of the 1,3-diyne moieties [35]. Thus diacetylenes typically polymerize rapidly in the solid state but not in solution. Polymerization is triggered by ultraviolet irradiation and proceeds via a 1,4-addition mechanism yielding a conjugated ene-yne backbone (Fig. 5). The reaction can be followed by the growth of the visible absorption band of the polymer. 

Thakur and Meyler [22] have reported the growth of thin-film single crystals of poly(diacetylenes) by a shear process that produces aligned areas of about 1 cm-from melts and about 50 mm- from solution. These thin-film crystals were reported to be four orders of magnitude larger than those previously prepared by Isoda [23]. 

Tokarski, Z., Epling, B., Natarajan, L. V., Cooper, T. M., Grinstead, T. M., Crane, R. L., and Adams, W. W., The nonlinear optical response of corona poled poly[(gamma-A-pentylamino-p-nitrobenzene) L-glutamate], Polym. Prepr., 34, 600-601 (1993). Thakur, M., and Meyler, S., Growth of large-area thin-film single crystals of poly(diacetylenes), Macromolecules, 18, 2341-2344 (1985). 

Thakur, M. and Meyler, S., Growth of large-area thin-film single crystals of poly(diacetylenes). 

Paley, M.S., D.O. Frazier, H. Abeledeyem et al. 1992. Synthesis. Vapor growth, polymerization, and characterization of thin films of novel diacetylene derivatives of pyrrole. The use of computer modeling to predict chemical and optical properties of these diacetylenes and poly(diacetylenes). JAm Chem Soc 114 (9) 3247-3251. 

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