The poly(ethylene oxide) (PEO)/water system is investigated using small-angle neutron scattering (SANS). This system associates to form hydrogen-bonded clusters at high enough concentrations. Two correlation lengths are observed: one long range representing cluster sizes and the other short range representing polymer chain correlations. Clusters are formed at a volume fraction of 4% hPEO in D2O. An LCST transition is obtained between a mixed phase (through hydrogen bonding) and a demixed two-phase region. Solvent deuteration is seen to enhance hydrogen bonding. Deuteration of the polymer backbone is seen to enhance hydrophobic interactions. The average polymer contrast match method fails due to the isotopic dependence of specific interactions. Pressure was seen to lower the LCST by breaking hydrogen bonds. At even higher temperature (beyond the boiling point of water) a UCST transition was observed.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据