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Thermoresponsive Stiffening with Microgel Particles in a Semiflexible Fibrin Network
We report temperature-responsive soft composites of semiflexible biopolymer networks (fibrin) containing dispersed microgel colloidal particles of poly(N-isopropylacrylamide) (pNIPAM) that undergo a thermodynamically driven deswelling transition above the lower critical solution temperature. Unlike...
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Published in: | Macromolecules 2019-04, Vol.52 (8), p.3029-3041 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | We report temperature-responsive soft composites of semiflexible biopolymer networks (fibrin) containing dispersed microgel colloidal particles of poly(N-isopropylacrylamide) (pNIPAM) that undergo a thermodynamically driven deswelling transition above the lower critical solution temperature. Unlike standard polymer–particle composites, decreasing the inclusion volume of the particles (by increasing temperature) is concomitant with a striking increase of the overall elastic stiffness of the composite. We observe such a behavior over a wide composition space. The composite elastic shear modulus reversibly stiffens by up to 10-fold over a small change in temperature from 25 to 35 °C. In isolation, the fibrin network and microgel suspension both soften with increased temperature, making the stiffening of the composites particularly significant. We hypothesize that stiffening is caused by the shrinking microgel particles that deform fibrin filaments, and modify the network structure. We develop a phenomenological model that quantifies this hypothesis, and the derived predictions are qualitatively consistent with our experimental data. |
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ISSN: | 0024-9297 1520-5835 |
DOI: | 10.1021/acs.macromol.9b00124 |