Intramolecular Charge Transfer Complexes as Fluorescence Probes for UV andVisible Light Induced Acrylate Polymerization

摘要

Intramolecular charge transfer complexes (ICTC) of derivatives of 1-diaminonaphthalene-5-sulfonamide (DANSYL AMIDE) such as 1-dimethylamino-naphthalene-5-sulfonyl-n-butylamide (1,5-DASB) and 2-dimethylamino-naphthalene-5-sulfonyl-n-butylamide (2,5DASB), were used as fluorescence probes for cure monitoring of photocurable polymer systems. This technique is based upon the difference in fluorescence intensity from the parallel and perpendicular conformations of the excited state of the complex, and is based on the dependence of the relative population of each conformation on the microviscosity of the system. As the curing reaction proceeds, the steady state fluorescence emission spectra of the probes were all found to exhibit hypsochromic spectral shifts due to the increase in matrix microviscosity. A linear correlation between the fluorescence intensity ratios (R=Ipar. / Iper.) and the extent of polymerization, measured by transmission FTIR spectrometry, was obtained for different types of acrylated polymers, cured with UV or visible (VIS) initiators. Intramolecular charge transfer, Visible light induced acrylate polymerization.