Azo-Containing Polymers with Degradation On-Demand Feature

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• 作者：Mathieu A. Ayer ; Yoan C. Simon ; Christoph Weder
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：April 26, 2016
• 年：2016
• 卷：49
• 期：8
• 页码：2917-2927
• 全文大小：546K
• 年卷期：0
• ISSN：1520-5835

文摘

Molecules comprising aliphatic azo moieties are widely used as radical polymerization initiators, but only a few studies have explored their usefulness as stimuli-responsive motifs in macromolecular constructs. The controlled degradation of azo-containing polymers has indeed remained largely unexplored. Here we present the syntheses of linear azo-containing polyamides and polyurethanes and report on their thermally and optically induced responses in solution and the solid state. We show that the stimuli-induced degradation behavior depends strongly on the nature of the polymer backbone, the state of matter, and in solution, on the nature of the solvent. The stimuli-responsive solid-state properties of the azo-containing materials may be particularly useful. In the case of the polyurethanes studied here, temperature- or light-induced cleavage of the azo motifs led to a controllable decrease in the molecular weight, which, in turn, caused a reduction of the elongation at break, modulus, and strength. The controlled degradation of the polymer in well-defined areas can be readily achieved via photopatterning, and this approach was shown to be useful to produce solid structures with graded mechanical properties.