Irradiation Langmuir-Blodgett film

The photochemistry of a phenyldiacrylic acid derivative has been studied in Langmuir-Blodgett films J The crystal structure of the major dimer formed on perdeuterioacetone-sensitized irradiation of f-butyl-2,5-dihydro-5,5-dimethyl-2-0X0-IH-pyrrole-l-carboxylate has been determined. Styryldicyanopyrazines undergo topochemical dimerisation when they are irradiated in the crystalline phase. ... 

Fig. 6. Optical absorption spectra ofthe mixed Langmuir-Blodgett film of all-rranj- arotene with barium stearate (1 10) measured at room temperature on normal irradiation with light polarized parallel to the x- ory-axis of the substrate.

Fig. 7. Plots for the absorbance of the mixed Langmuir-Blodgett film ofall-fro/w-)3-carotene with barium stearate (1 10) detected on irradiation with 445 nm light at any incident angles. Filled circles represent the results obtained on irradiation with s-polarized light. Solid lines show the results ofthe theoretical calculations based on the axis model assuming n= 1.46 and Q./C = 0.5...

Figure 16 UV-Vis absorption spectra of films of 46 irradiated at 365 nm. (a) Spin-coated film, (b) Langmuir-Blodgett multilayer film. (Reprinted with permission from Stumpe et al. [29]. Copyright 1996 American Chemical Society.)...

The Langmuir Blodgett technique offers the unique advantage to cover holes in perforated substrates. It has been shown, that films of tethered polyisoprenes with photoreactive side groups can be cross linked on the water surface via irradiation [27]. These cross-linked films of 40 nm thickness can be transferred to grids and perforated substrates and can span holes of up to 300 jum in diameter. Since these freely suspended films are made out of a cross-linked polymer melt, they show rubber elastic behaviour. 

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