...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The European physical journal, E. Soft matter >Dynamics of propylene glycol and its oligomers confined in clay
【24h】

Dynamics of propylene glycol and its oligomers confined in clay

机译：限制在粘土中的丙二醇及其低聚物的动力学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The dynamics of propylene glycol (PG) and its oligomers 7-PG and PPG, with M_W = 4000 (about 70 monomers), confined in a Na-vermiculite clay have been investigated by quasi-elastic neutron scattering and dielectric spectroscopy. The liquids are confined to a single molecular layer between the clay platelets, thus giving a true 2D liquid. The results show that the average relaxation time <τ>, deduced from neutron scattering at a momentum transfer Q of about 1 A~(-1), is in perfect agreement with the dielectric α-relaxation time, although neutron scattering does not only probe the main (α-) relaxation, but all motions of hydrogens on the experimental time scale. At room temperature 1/<τ> is proportional to Q~2, indicating that the relaxations are mainly due to ordinary translational diffusion. The most unexpected finding is that <τ> (or the dielectric α-relaxation time) is almost unaffected by the 2D confinement, in contrast to the dielectrically active normal mode of PPG which is substantially slower in the confinement. Only the 7-mer has a significantly slower segmental translational diffusion in the clay. The results suggest that the interactions to the clay surfaces are weak and that the present 2D confinement has a very small influence on the time scale of all our observed relaxation processes, except the normal-mode relaxation.
机译：通过准弹性中子散射和介电谱研究了丙二醇（PG）及其低聚物7-PG和PPG（M_W = 4000（约70个单体），被限制在Na con石粘土中）的动力学。液体被限制在粘土薄片之间的单个分子层中，因此产生了真正的2D液体。结果表明，尽管中子散射不仅探测了中子散射，但由中子散射在约1 A〜（-1）的动量传递Q下推导的平均弛豫时间<τ>与电介质α弛豫时间完全吻合。主要的（α-）弛豫，但氢在实验时间范围内的所有运动。在室温下1 / <τ>与Q〜2成正比，表明弛豫主要归因于普通的平移扩散。最出乎意料的发现是<τ>（或介电α弛豫时间）几乎不受2D限制的影响，与之相比，PPG的介电活性正常模式的速度要慢得多。仅7聚体在粘土中具有明显较慢的节段平移扩散。结果表明，与黏土表面的相互作用较弱，并且当前的二维限制对我们观察到的所有松弛过程的时间尺度都具有很小的影响，除了正常模式松弛。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号