Diacetylene films deposition

Chemical properties of deposited monolayers have been studied in various ways. The degree of ionization of a substituted coumarin film deposited on quartz was determined as a function of the pH of a solution in contact with the film, from which comparison with Gouy-Chapman theory (see Section V-2) could be made [151]. Several studies have been made of the UV-induced polymerization of monolayers (as well as of multilayers) of diacetylene amphiphiles (see Refs. 168, 169). Excitation energy transfer has been observed in a mixed monolayer of donor and acceptor molecules in stearic acid [170]. Electrical properties have been of interest, particularly the possibility that a suitably asymmetric film might be a unidirectional conductor, that is, a rectifier (see Refs. 171, 172). Optical properties of interest include the ability to make planar optical waveguides of thick LB films [173, 174]. 

Besides single crystals, disubstituted diacetylene polymer thin films can be obtained for waveguide applications by evaporation, solidification, or deposition of the diacetylene monomers by the Langmuir-Blodgett approach, which allows film thicknesses to be controlled at the molecular level. These diacetylene films can be patterned using selective polymerization techniques such as developed for... 

The above findings are directly relevant to the study of diacetylene films. Since homoepitaxy does not occur in the presence of multivalent metal ions, the emphasis should be shifted to materials which can be deposited on a pure water subphase - some have already been demonstrated. It is predicted that these materials will also display heteroepitaxy with fatty acid monolayers. 

Studies of the solid state photopolymerization of deposited multilayer films reveal that uv induced photopo1ymerizati0n of disubstituted diacetylenes... 

Polydiacetylenes. Dimethanol-diacetylene (H0CH2C=C-C=CCH OH) (DMDA) was used as received from Farehan Chemical Co. Diphenyl urethane-diacetylene -NH-COO-(CH2) -C=C-C=C-(CH2) -OOC-NH- < ) (TCDU) wasused as received from Allied Chemical Co. Both monomers were successfully deposited as epitaxial films on various alkali halides from vapor and solution phases. The following conditions were used for these crystallizations vapor phase DMDA = 40 C at 10 torr, vapor phase TCDU = 150 C at 10 torr, solution (1 wt % in toluene) phase DMDA = 70 C for 30 minutes, solution (.4 wt % in ethyl acetate) phase TCDU = 30 C for 5 minutes. 

---