利用光散射為工具，觀察低濃度下poly(4-vinylpyridine)於氯仿溶液的交互擴散現象。氯仿對於P4VP為良溶劑。在動態光散射的量測裡，intensity autocorrelation function顯示溶液內僅存在擴散模式。換言之，在此系統裡，交互擴散係數的主要貢獻來自滲透模數，溶液應力模數則可以忽視。溶液內的擴散運動可以觀察到分為兩種速度，快慢模式皆清楚地顯示 相依關係。固定溫度下，發現交互擴散係數隨著高分子濃度的增加而降低。此外，隨著溫度下降，交互擴散係數也隨著線性下降，藉由外推法，延伸交互擴散係數為零時得到臨界溫度，而此即為溶液發生相變化的溫度。

A light scattering study of dilute solutions consisting of poly(4-vinylpyridine) dissolved in chloroform has been carried out. Chloroform is a good solvent for P4VP. Dynamic light scattering measurements show only a diffusion mode in the intensity autocorrelation function for freshly prepared solutions, but two modes are present as the solution ages. The two modes found in P4VP/CHCl3 solution both show a clear q dependence, q being the magnitude of the scattering wave vector, thus indicating that both are diffusive modes. For this system, the diffusion coefficient is found to be mainly determined by the osmotic modulus, with the solution stress modulus making a negligible contribution. A decrease of mutual diffusion coefficient with increasing polymer concentration is observed. As the temperature of the solution is lowered, the mutual diffusion coefficient decreases linearly. Extrapolation of the mutual diffusion coefficient to zero yields the critical temperature, at which the P4VP/CHCl3 solution undergoes a phase transition.

論文摘要
第一章 簡介 1
第二章 原理 3
2.1 Fluctuation and Time-Correlation Function, 3
2.2 Fluctuation in Dielectric Constant and Light Scattering, 4
2.3 Homodyne Correlation Function for Diffusion, 7
2.4 Hydrodynamic Equation for Binary Mixture, 9

第三章 實驗 11
3.1 樣品配製, 11
3.2 動態光散射量測, 13
第四章 結果與討論 15
結論 34
參考資料 35

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