科研之友
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摘要
The goal of the paper is the study of the behaviour of some azo groups containing polymers on UV irradiation. Two sets of polymers have been studied: polyethers containing azobenzene groups in the main chain and polysiloxanes with azo groups in the side chain. For the polyethers, the behavior during UV irradiation has been studied in condensed state, while the polysiloxanes were investigated in solution. For the polymers in condensed state, the study was made based on electronic absorption spectra, while the solutions were investigated based on viscosimetric measurements. In both cases, the UV irradiation induce conformational modifications, the rate with which polymers responded depending on the aggregation state. For the systems in condensed state, the rate is slow, 15 to 20 min being necessary for a maximum number of transitions from trans to cis. In the case of solutions, the necessary time is only 2 min. The full reversibility of the photoisomerization processes of the azo groups confers to the investigated compounds potential utilization for controlled release of drug molecules, immobilized in a polymeric matrix.
- 出版日期2004-9
