Polymer Dynamics in Nanochannels of Porous Silicon: A Neutron Spin Echo Study
Polymer Dynamics in Nanochannels of Porous Silicon: A Neutron Spin Echo Study
复制标题
多孔硅纳米通道中的聚合物动力学：中子自旋回波研究
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
P. Huber
中科院分区：
文献类型：
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作者：
A. Kusmin;Simon Gruener;A. Henschel;Nicolas Raphael de Souza;J. Allgaier;D. Richter;P. Huber
在 Q = 0.05、0.08 和 0.11 A -1 处记录了限制在多孔硅（平均孔径：13 nm）中的聚环氧乙烷（PEO）熔体的中子自旋回波谱，并成功地根据二态模型进行了分析，其中吸附在孔壁上的链表现出比块状链慢得多的内部动力学，并且它们的质心不移动，而自由链具有块状内部动力学并在无限范围内扩散。圆柱体位于毛孔的中心。对于 PEO 3 kg/mol (3k)，该圆柱体的半径为 1.4 nm；这对应于吸附层的厚度大约等于弗洛里半径。与无法辨别质量扩散中心细节的 PEO 10k 相反，对于 PEO 3k，发现沿孔的扩散速率小于沿径向的扩散速率。
Neutron spin echo spectra of poly(ethylene oxide) (PEO) melts confined in porous silicon (the mean pore diameter: 13 nm) were recorded at Q = 0.05, 0.08, and 0.11 A -1 and successfully analyzed in terms of a two-state model, where chains adsorbed to the pore walls exhibit much slower internal dynamics than in the bulk and their centers-of-mass do not move, while free chains have bulklike internal dynamics and diffuse within an infinite eylinder in the center of the pore. The radius of this cylinder was found to be 1.4 nm for PEO 3 kg/mol (3k); this corresponds to the thickness of the adsorbed layer to be approximately equal to the Flory radius. As opposed to PEO 10k, for which details on the center of mass diffusion could not be discerned, for PEO 3k the diffusion rate along the pore was found to be smaller than that in the radial direction.