Fast and Large Shrinking of Thermoresponsive Hydrogels with Phase-Separated Structures
Autor: | Im Kyung Han, Jihoon Han, Youn Soo Kim, Kyojin Ahn, Taehun Chung |
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Rok vydání: | 2021 |
Předmět: |
poly(N-isopropylacrylamide) (PNIPAAm)
Phase transition Materials science Polymers and Plastics Kinetics Bioengineering 02 engineering and technology 010402 general chemistry 01 natural sciences Article lcsh:Chemistry Biomaterials lcsh:General. Including alchemy Phase (matter) lcsh:Inorganic chemistry lcsh:Science Porosity hydrogels Shrinkage Aqueous solution Organic Chemistry 021001 nanoscience & nanotechnology lcsh:QD146-197 0104 chemical sciences lcsh:QD1-999 Polymerization Chemical engineering shrinking behavior Self-healing hydrogels lcsh:Q thermoresponsive phase separation 0210 nano-technology lcsh:QD1-65 |
Zdroj: | Gels, Vol 7, Iss 18, p 18 (2021) Gels Volume 7 Issue 1 |
ISSN: | 2310-2861 |
Popis: | Thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels have been attracting attention in a variety of functional materials, such as biomaterials, because they exhibit a volume phase transition phenomenon near physiological temperatures. However, the slow kinetics and small volume shrinkage of bulk PNIPAAm hydrogels upon heating greatly limit their practical application. Here, we report PNIPAAm hydrogels with phase-separated structures that exhibited ultrafast shrinking upon heating. The phase separation into a PNIPAAm-rich phase and a water-rich phase was formed through aqueous polymerization in the presence of NaClO4 salt. Through structural analysis of the hydrogels, a topologically heterogeneous and porous structure was observed, which was highly dependent on the NaClO4 concentration in the polymerization step. Compared to conventional PNIPAAm hydrogels, the phase-separated hydrogels exhibited much faster and larger shrinkage upon heating. Simultaneously, the hydrogels quickly released a large amount of water owing to the effective water channels inside them. The present method can be widely applied to general hydrogels, and it can address the numerous limitations of hydrogels in terms of operating programmability and deformation efficiency. |
Databáze: | OpenAIRE |
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