Controlling the electrostatic interaction using a thermal signal to structurally change thermoresponsive nanoparticles
Controlling the electrostatic interaction using a thermal signal to structurally change thermoresponsive nanoparticles
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DOI：
10.1016/j.colsurfa.2019.05.052
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发表时间：
2019-09
期刊：
影响因子：
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通讯作者：
J. Akimoto;Hsiu-Pen Lin;Yaw-Kuen Li;Yoshihiro Ito
中科院分区：
文献类型：
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作者：
J. Akimoto;Hsiu-Pen Lin;Yaw-Kuen Li;Yoshihiro Ito
采用可逆加成-断裂链转移聚合法合成了聚甲基丙烯酸苄酯-b-聚丙烯酸-b-聚N-异丙基丙烯酰胺（PBzMA-b-PAAc-b-PIPAAm）负电荷温敏聚合物。在低于PIPAAm链的低临界溶解温度（LCST）时，PAAc-b-PIPAAm形成了具有温敏电晕的核壳聚合物胶束。由PBzMA-b-PIPAAm组成的非离子型温敏聚合物胶束在形成电晕的PIPAAm链的疏水相变后表现出广泛的胶束间聚集。相反，PAAc链插入到温敏胶束中由于胶束之间的静电排斥而保持其在PIPAAm的LCST以上的电导率。PAAc链较短的胶束由于PIPAAm链在胶束表面的延伸，在LCST以下抑制了PAAc所产生的负电荷的作用。相反，由于LCST上方的PIPAAm层的塌陷而出现负电荷性质。其静电行为的这种温度响应性变化使得胶束能够响应于LCST上的温度变化来控制带相反电荷的分子的吸附和解吸。
The negatively charged thermoresponsive polymers poly(benzyl methacrylate)-b-poly(acrylic acid)-b-poly(N-isopropylacrylamide) (PBzMA-b-PAAc-b-PIPAAm) were prepared by reversible-addition fragmentation chain transfer polymerization. The polymer formed core-shell polymeric micelles possessing a thermoresponsive corona composed of PAAc-b-PIPAAm below the lower critical solution temperature (LCST) of the PIPAAm chain. The nonionic thermoresponsive polymeric micelle composed of PBzMA-b-PIPAAm exhibited extensive inter-micellar aggregation after the hydrophobic phase transition of the corona-forming PIPAAm chains. In contrast, insertion of the PAAc chain into the thermoresponsive micelle maintained its dispersibility above the LCST of PIPAAm because of the electrostatic repulsion between the micelles. The micelles with short PAAc chains suppressed the effect of the negative charge derived from PAAc below the LCST because of the extended PIPAAm chain on the micellar surface. In contrast, the negative charge property appeared due to collapse of the PIPAAm layer above the LCST. This thermoresponsive change in its electrostatic behavior enables the micelle to control the adsorption and desorption of oppositely charged molecules in response to the temperature change across the LCST.