| 초록 |
In this work, we have modified the chemical structure of the poly(N-isopropylacrylamide) (PNIPAm) based polymers, achieving hydrogels capable of programmable thermal behaviors. We could prepare the multi-components copolymers having a compositional gradient by slow addition of the monomers in the reaction mixture during free-radical polymerization. We found that prepared copolymers exhibit nearly linear transmittance change over a wide temperature range due to the gradient hydrophilic–hydrophobic balances depending on the monomer composition. Furthermore, poly(N-isopropylacrylamide)-graft-methylcellulose hydrogel (PNIPAm-g-MC) was prepared through the grafting of PNIPAm onto a MC backbone and simultaneous cross-linking of the chains. Base on the large thermal hysteresis of PNIPAm-g-MC in its volume change, programmable volume phase transition could be triggered by visible light irradiation and excessive cooling, which can be used to fabricate the static motion actuator. |
