Collapse and Swelling of Thermally Sensitive Poly(N-isopropylacrylamide) Brushes Monitored with a Quartz Crystal Microbalance

2006-07-18 17:25  下载量:178

资料摘要

资料下载

Thermally sensitive poly(N-isopropylacrylamide) (PNIPAM) brushes grafted on SiO2-coated quartz crystal surface were prepared with a surface-immobilized initiator. Using quartz crystal microbalance (QCM), we investigated the collapse and swelling of the brushes in water in real time. Both frequency and dissipation of PNIPAM brushes were found to gradually change throughout a temperature range 20-38 °C, indicating that PNIPAM brushes undergo a continuous collapse transition in contrast with PNIPAM chains free in dilute solution exhibiting a sharp coil-to-globule transition. This result is in accordance with the previous theoretical prediction. The nonuniformity and stretching of PNIPAM brushes as well as the cooperativity between collapse and dehydration transitions are thought to be responsible for the continuity. On the other hand, a hysteresis was also observed in the cooling process. This is not only due to the intrachain and interchain interactions formed in the collapsed state but also to the nonuniform structure and stretching of the high-density brushes.

资料下载

文献贡献者

相关资料 更多

相关产品

当前位置: 凯戈纳斯 资料 Collapse and Swelling of Thermally Sensitive Poly(N-isopropylacrylamide) Brushes Monitored with a Quartz Crystal Microbalance

关注

拨打电话

留言咨询