ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The solid state polymerization of disubstituted diacetylene single crystals can lead to polymer single crystals of macroscopic dimensions. Polymer single crystals with a volume of half a cubic centimeter can be produced by thermal or by γ-ray polymerization. Details of the reaction are revealed if it is initiated by UV-light. - Recent spectroscopic and holographic experiments during the photoinitiated reaction of the by far most investigated diacetylene TS are reviewed (TS = P-toluene-sulfonyl-oxymethylene substituted diacetylene). - Electron Spin Resonance (ESR) and Electron Nuclear Double Resonance (ENDOR) spectra at 4.2 K identify bicarbene oligomers and their detailed structures as intermediate states during the reaction. Bicarbene oligomers consisting of up to thirteen monomer units are analyzed and specified spectroscopically. - Laser flash photolysis is able to analyze the kinetics of the first reaction steps separately and within a large temperature range up to room temperature. The UV-flash initiates the reaction which subsequently proceeds exothermic and thermally activated. The activation energies are measured to be almost equal for each step following the photoinitiation: ΔE = 0.25 eV/monomer. The relevant rate constants for the first steps are of the order of 1 vs at room temperature and 1 ms at 180 K, respectively. Single crystal polymer gratings produced by two interfering UV-laser beams at the surface of the monomer single crystal show that holograms with both, high spatial resolution of more than 1600 lines per mm and high efficiency of up to more than 30 % can be stored and read out without any developping processes.
Additional Material:
26 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1985.020121985108
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