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Azo-Containing Polymers with Degradation On-Demand Feature
- Macromolecules. - 2016, vol. 49, p. 2917–2927
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.
- Faculté des sciences et de médecine
- AMI - Chimie des polymères et matériaux
- Weder2016Macromolecules.pdf: 34
- Weder2016Macromolecules_SI.pdf: 16