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  本文選題：膠體系統(tǒng)　切入點(diǎn)：橋連接模型　出處：《清華大學(xué)》2016年博士論文

【摘要】：膠體系統(tǒng)在日常生活及工業(yè)應(yīng)用中廣泛存在,對膠體粒子間作用機(jī)制的研究對于膠體系統(tǒng)性能的優(yōu)化具有重要意義。在橋連接作用下,膠體系統(tǒng)會出現(xiàn)單相-多相-單相這一奇特的相變過程,盡管已有的研究已經(jīng)提出了橋連接作用這一假設(shè),但是并未對其進(jìn)行驗(yàn)證。小角中子散射技術(shù)可有效研究納米到微米尺度材料的結(jié)構(gòu),因此常常用于膠體系統(tǒng)的結(jié)構(gòu)研究。本文基于小角散射理論,建立了橋連接模型,并對膠體系統(tǒng)的相圖信息進(jìn)行了理論及實(shí)驗(yàn)研究。主要內(nèi)容如下:(1)在小角散射理論框架下,利用多組分粘性硬球模型構(gòu)建橋連接模型,對系統(tǒng)關(guān)鍵參數(shù)進(jìn)行了解析求解,包括其結(jié)構(gòu)因子、散射強(qiáng)度理論曲線以及相圖中的旋節(jié)線、最大橋連接吸引力和等效硬球作用點(diǎn);(2)建立了橋連接作用下雙組分粘性硬球系統(tǒng)到單組分系統(tǒng)的映射模型,使單組分粘性硬球系統(tǒng)的研究成果,如逾滲線與雙節(jié)線的結(jié)論可直接應(yīng)用于橋連接系統(tǒng);(3)研究橋連接作用下特定實(shí)驗(yàn)系統(tǒng)(PS和PNIPAM混合系統(tǒng))的理論相圖并與實(shí)驗(yàn)觀測結(jié)果對比,驗(yàn)證了該模型的有效性;(4)利用橋連接模型,研究組分相對大小和組分間粘性參數(shù)對系統(tǒng)相圖的影響,還研究了大組分粒子間等效作用力的結(jié)構(gòu)特征。數(shù)值擬合結(jié)果可為實(shí)驗(yàn)操作提供指導(dǎo);(5)通過小角中子散射實(shí)驗(yàn)研究牛血清蛋白(BSA)和氯化釔(YCl3)混合系統(tǒng),并利用橋連接模型進(jìn)行數(shù)據(jù)分析,研究了不同Y3+濃度下系統(tǒng)的散射曲線以及BSA蛋白分子組成和形狀的變化情況。本論文證明了雙組分膠體系統(tǒng)中橋連接作用的存在,為實(shí)驗(yàn)系統(tǒng)中單相-雙相-單相的相變過程提供了更深層次的物理解釋。本論文建立的橋連接系統(tǒng)到單組分粘性硬球系統(tǒng)的映射模型,使許多已有的單組分粘性硬球系統(tǒng)的研究成果可以直接應(yīng)用于橋連接系統(tǒng),極大簡化了橋連接系統(tǒng)的研究難度。同時,本文首次利用橋連接模型和小角中子散射技術(shù)研究復(fù)雜膠體系統(tǒng),為小角散射領(lǐng)域的實(shí)驗(yàn)物理學(xué)家們提供了一種新的行之有效的研究方法,也為類似系統(tǒng)的研究提供了理論和實(shí)驗(yàn)支撐。
[Abstract]:Colloidal system is widely used in daily life and industry. The study on the mechanism of colloidal particle interaction is of great significance to the optimization of colloidal system performance. The colloidal system has a peculiar phase transition process of single-phase to polyphase, although the hypothesis of bridging interaction has been proposed in previous studies. However, it has not been verified. The small-angle neutron scattering technique can effectively study the structure of nanometer-to-micron scale materials, so it is often used to study the structure of colloidal systems. Based on the theory of small-angle scattering, a bridge connection model is established in this paper. The phase diagram information of the colloidal system is studied theoretically and experimentally. The main contents are as follows: (1) in the framework of small angle scattering theory, the bridge connection model is constructed by using the multi-component viscous hard sphere model, and the key parameters of the system are solved analytically. Including its structure factor, theoretical curve of scattering intensity, spin nodal line in phase diagram, maximum bridge connection attraction and equivalent hard sphere action point, the mapping model of two-component viscous hard sphere system to one-component system under bridge connection is established. The results of single-component viscous hard sphere system, such as the conclusion of percolation line and double nodal line can be directly applied to bridge connection system, are used to study the theoretical phase diagram of a specific experimental system under bridge connection and the mixed system of PS and PNIPAM), and the results are compared with the experimental results. The validity of the model is verified. (4) the influence of the relative size of the study group and the viscosity parameters between components on the phase diagram of the system is verified by using the bridge connection model. The structural characteristics of the equivalent force between large component particles were also studied. The numerical fitting results can provide guidance for the operation of the experiment. The mixed system of bovine serum protein (BSA) and yttrium chloride yttrium chloride (YCL _ 3) is studied by small angle neutron scattering experiment. The scattering curves of the system and the changes of the molecular composition and shape of BSA protein under different concentrations of Y _ 3 were studied by using the bridge connection model. The existence of bridging interaction in the two-component colloid system was proved in this paper. It provides a deeper physical explanation for the phase transition process of single-phase, two-phase and single-phase in the experimental system. In this paper, the mapping model from bridge connection system to single-component viscous hard sphere system is established. Many existing research results of single-component viscous hard ball system can be directly applied to bridge connection system, which greatly simplifies the research difficulty of bridge connection system. At the same time, In this paper, the bridge-connected model and small-angle neutron scattering technique are used to study the complex colloidal system for the first time, which provides a new and effective method for the experimental physicists in the field of small-angle scattering. It also provides theoretical and experimental support for the research of similar systems.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：O571.5

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本文編號：1675893