Staat van de ambtelijke dienst 2015 De overheid in tijden van verandering

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Thermal and photoinduced polymerization of thin diacetylene films. 1. Phthalimido-substituted diacetylenes

A series of phthalimido-substituted (Pht) diacetylenes with the structure Pht-(CH2)n-CC-CC-(CH2)m-R was synthesized. The influence of the length of the alkyl spacer n between the phthalimido group and the diacetylene group, the length of the alkyl spacer m and an additional polar group R on the thermal and UV-induced polymerization was investigated by systematic variation of n, m, and R (for R = H and m = 8, n = 1, 3, 4, 5, 8, 9; for n = 9 and m = 3, R = H, CH2OH, COOH). All synthesized compounds underwent thermal polymerization. The polymerization temperature increased with longer n spacer or shorter m spacer, and no effect was observed on variation of R. For UV-induced polymerization, a spacer length n of more than four carbon atoms was necessary. Introduction of a hydrogen-bond-forming hydroxyl or carboxyl group at the other side of the diacetylene yielded polymers with a significantly higher degree of conjugation and also improved film formation on quartz enormously

Long-Lived Mobile Charge Carriers Formed on Photoexcitation of UV-Polymerized, Spin-Coated Films of Arylimido-Spacer-Diacetylene Derivatives

The photopolymerization of spin-coated films of diacetylene derivatives containing phthalimido or naphthaldiimido moieties has been studied by monitoring the increase in the optical absorption in the visible region on irradiation at 308 nm. The phthalimido derivatives form blue polymers with absorption maxima at ca. 630 nm, corresponding to a highly conjugated, close to planar polydiacetylene (PDA) backbone configuration. The naphthaldiimido derivative yields a red polymer with an absorption maximum at 535 nm, indicating a backbone structure with a substantially reduced degree of -bond conjugation. The initial, "low-dose" quantum yields for monomer conversion, based on the total number of photons absorbed at 308 nm, range from 2 to 20. Monomer conversions up to ca. 50re found. The polymerized films are found to be photoconductive using the time-resolved microwave conductivity technique (TRMC). Mobile charge carriers are suggested to be formed via the triplet state of the arylimido moieties which undergoes long-distance charge transfer to polydiacetylene chains to form the arylimido radical anion and the mobile PDA radical cation or "hole". A maximum value of 1.4 x 10-2 cm2/(V s) for the product of the quantum yield for charge carrier formation and the hole mobility is found. The photoconductivity of the "blue" polymer is approximately an order of magnitude larger than for the "red" variety. This is attributed to a higher mobility of PDA holes in the former compound, resulting from the higher degree of backbone conjugation. The lifetime of the mobile carriers extends well into the microsecond region, which is considerably longer than previously found on direct ionization of PDA chains

Toll-Like Receptor (TLR2 and TLR4) Polymorphisms and Chronic Obstructive Pulmonary Disease

10.1371/journal.pone.0043124PLoS ONE78e4312