聚(异丙基丙烯酰胺)-b-聚(4-乙烯基吡啶)胶束负载铂纳米粒子的温度响应性催化

The Preparation of Pt Nano-Catalyst with Micelles of (PNIPAM-b-P4VP) and Use in the Thermo-responsive Catalysis

嵌段共聚物聚（N-异丙基丙烯酰胺）-b-聚（4-乙烯基吡啶）（PNPIAM—b—P4VP）在pH6．5的水溶液中自组装成，以聚（4-乙烯基吡啶）为胶束的核，以热响应聚（N-异丙基丙烯酰胺）为胶束壳的球形胶束．通过与4VP基络合作用，将氯铂酸（H2PtCl6）导人胶束的核中，原位还原获得胶束负载2～4nm的铂纳米粒子的温度敏感型催化体系．结果显示，最低临界溶解温度（LCST）为33℃，在LCST以下，催化反应速率会随着温度的升高而提高；在LCST以上，PNPIAM嵌段变成疏水而塌缩在催化剂表面，阻碍了反应物的扩散，因此胶束负载的铂纳米粒子的催化活性会随着温度的上升而下降．

The block copolymer poly （N-isopropylacrylamide） -b-poly （ 4-vinyl pyridine ） （PNIPAM-b-P4VP） was self-assembled into core-corona micelles with the P4VP block as core and the thermoresponsive PNIPAM block as corona in pH 6.5. The diameter of the micelles was about 40 nm. Pt nanoparticles of size ranging from 2 to 4 nm were loaded in the micelles to form a responsive catalyst, the activity of which could be modulated due to the thermoresponsive PNIPAM. The lower critical solution temperature （LCST） was about 33℃. Below LCST, the catalytic activity of the micelle-supported Pt nanoparticles increased with the increase in temperature. However, above LCST, PNIPAM block turn into hydrophobic and collapsed on the Catalyst, which decelerated diffusion of the reactants. The catalytic activity of the micelle-supported Pt nanoparticles decreased with the increase in temperature.