Initial Stages of Polymer Interdiffusion Studied by Neutron Reflectometry
Initial Stages of Polymer Interdiffusion Studied by Neutron Reflectometry
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中子反射法研究聚合物相互扩散的初始阶段
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
T. Springer
中科院分区：
文献类型：
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作者：
M. Stamm;S. Huettenbach;G. Reiter;T. Springer
通过中子反射计研究了氘化聚苯乙烯和质子化聚苯乙烯两层薄膜之间界面处相互扩散的时间依赖性。可以解决不同的时间制度。首先，最初分离良好的分子链段在约 3 nm 的距离内发生非常快速的混合。在中间时间，没有观察到链穿过界面的显着的进一步移动。发现了第三种时间状态，其链段穿过界面的运动指数较大。然而，与大扩散时间下预期的 √t 行为相比，它仍然要慢得多，其中扩散路径大于回转半径。使用假设聚合物界面处的误差函数型密度分布的简单模型来分析数据，但一般结论并不依赖于特定模型。结果根据聚合物扩散的蠕动模型进行讨论。
The time dependence of interdiffusion at the interface between two thin films of deuterated and protonated polystyrene has been investigated by neutron reflectometry. Different time regimes can be resolved. First, a very fast intermixing of chain segments of the originally well-separated molecules over a distance of approximately 3 nm takes place. At intermediate times no significant further movement of the chains across the interface is observed. A third time regime with a larger exponent for the movement of chain segments across the interface is found. It is, however, still considerably slower as compared to the √t-behaviour expected at large diffusion times, where the diffusion path is larger than the radius of gyration. Data are analysed with a simple model assuming an error-function-type density profile at the polymer interface, but the general conclusions do not depend on the specific model. Results are discussed in terms of the reptation model of polymer diffusion.