本文選題：聚合物納米復(fù)合材料 + 分子動(dòng)力學(xué)模擬　； 參考：《浙江理工大學(xué)》2017年碩士論文

【摘要】：聚合物納米復(fù)合材料有著區(qū)別于純聚合物的更好的機(jī)械、力學(xué)及光學(xué)等性能,這使其在聚合物物理和材料科學(xué)領(lǐng)域受到了廣泛關(guān)注。通常材料的宏觀性能由其微觀相所決定。聚合物納米復(fù)合材料的宏觀性能則主要由聚合物基質(zhì)中納米顆粒的分散情況所決定。因此為了能夠有效控制聚合物納米復(fù)合物的宏觀性能,必須深入研究聚合物與納米粒子之間的相互作用機(jī)制,分析探索納米粒子在聚合物納米復(fù)合體系中的相變化情況。由于闡明聚合物納米粒子復(fù)合材料的各相的相互作用機(jī)制在實(shí)驗(yàn)和理論中較為困難,通過計(jì)算模擬的方法更有利于我們對(duì)聚合物納米復(fù)合材料的研究。本文使用分子動(dòng)力學(xué)模擬方法研究了局限在兩平行硬板間的聚合物納米粒子復(fù)合物體系,觀察到了球形納米粒子被扁平聚合物鏈修飾結(jié)構(gòu)可控晶體現(xiàn)象。當(dāng)局限復(fù)合體系納米粒子的數(shù)目足夠高,能顯著干擾鏈的構(gòu)象時(shí),為了最小化熵?fù)p失,聚合物鏈取代納米粒子在基底表面聚集。使納米粒子的濃度遠(yuǎn)高于聚合物鏈的濃度會(huì)導(dǎo)致納米粒子被夾于兩個(gè)聚合物鏈的薄層之間,并在體系中心區(qū)域中形成有序排列。而由緊密關(guān)聯(lián)團(tuán)組成的聚合物鏈的標(biāo)度模型的提供闡明了薄聚合物層的形成和納米粒子的結(jié)晶背后的物理機(jī)制。通過調(diào)節(jié)聚合物鏈和納米粒子的體積濃度,顯示結(jié)晶的納米粒子的有序結(jié)構(gòu)是可調(diào)節(jié)的。同時(shí),我們又通過分子動(dòng)力學(xué)模擬測(cè)量了絕熱體系中表面分離的納米粒子在絕熱聚合物間的間接相互作用力。由于熵效應(yīng),通過變化絕熱體系中的聚合物濃度、聚合物鏈長及納米粒子尺寸等條件,模擬證實(shí)了分離間距超出了吸引力范圍的納米粒子之間的排斥存在,且提高聚合物濃度或增大納米粒子尺寸能使吸引力和排斥力單調(diào)增大。作為納米粒子間分離間距的函數(shù)的間接相互作用力對(duì)半稀釋聚合物的聚合物鏈長度沒有依賴性,作用范圍也僅受聚合物濃度的影響。最后,我們通過計(jì)算圍繞納米粒子的單體的徑向分布函數(shù)證實(shí)了間接力的存在。通過本文研究,我們發(fā)現(xiàn)了局限復(fù)合體系下納米粒子在聚合物膜間的結(jié)構(gòu)可控結(jié)晶現(xiàn)象,并通過對(duì)納米粒子二體間接作用力的計(jì)算分析了解到絕熱復(fù)合體系中各相的相互作用機(jī)制,初步闡明了局限體系靜態(tài)相結(jié)構(gòu)形成的原因。模擬研究的結(jié)果也將使我們對(duì)于聚合物納米復(fù)合體系中各相相互作用機(jī)制及其導(dǎo)致的相應(yīng)相行為有了更加深入的了解和掌握。
[Abstract]:Polymer nanocomposites have better mechanical, mechanical and optical properties different from pure polymers, which have attracted wide attention in the field of polymer physics and material science. The macro properties of the materials are usually determined by their microscopic phases. The macro properties of the polymer nanocomposites are mainly from the nanocomposites in the polymer matrix. The dispersion of particles is determined. So in order to effectively control the macro properties of polymer nanocomposites, the interaction mechanism between polymer and nanoparticles must be deeply studied and the phase change of nanoparticles in the polymer nanocomposite system is analyzed and explored. The interaction mechanism of phase is more difficult in experiment and theory. The method of calculating simulation is more beneficial to the study of polymer nanocomposites. In this paper, the polymer nanoparticle complex system limited to two parallel hard plates is studied by molecular dynamics simulation, and the spherical nanoparticles are observed to be flat. Polymer chain modified structure controlled crystal phenomenon. When the number of limited composite nanoparticles is high enough to interfere with the conformation of the chain, the polymer chain is replaced by the nanoparticles on the substrate surface to minimize the entropy loss. The nanoparticle concentration is much higher than the concentration of the polymer chain, which will lead to two polymerization of nanoparticles. An orderly arrangement between the thin layers of the chain, and an orderly arrangement in the central region of the system. The scale model of the polymer chain composed of tightly connected groups illustrates the formation of the thin polymer layer and the physical mechanism behind the crystallization of the nanoparticles. The crystalline nanoparticles are displayed by adjusting the volume concentration of the polymer chains and nanoparticles. The ordered structure is adjustable. At the same time, we have also measured the indirect interaction force between the particles separated by the surface in the adiabatic system by molecular dynamics simulation. The entropy effect, by changing the polymer concentration in the adiabatic system, the length of the polymer chain and the size of the nanoparticles, has proved the separation. The attraction and repulsion can be increased monotonously by increasing the concentration of the polymer or increasing the size of the nanoparticles. The indirect interaction force, as a function of the separation space between the nanoparticles, has no dependence on the length of the polymer chain of semi diluted polymers and the scope of action. In the end, we confirm the existence of the inter force by calculating the radial distribution function of the monomer around the nanoparticles. Through this study, we found the structure controlled crystallization between the nanoparticles in the polymer film under the confined composite system and the calculation of the indirect force of the two body of the nanoparticles. The interaction mechanism of each phase in the adiabatic composite system is analyzed and understood. The reasons for the formation of the static phase structure in the limited system are clarified. The results of the simulation study will also make us understand and master the interaction mechanism and the corresponding phase behavior in the polymer nanocomposite system.

【學(xué)位授予單位】：浙江理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.1;O643.36

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 曹學(xué)正;Merlitz Holger;Sommer Jens-Uwe;吳晨旭;;Entropy dominated behaviors of confined polymer-nanoparticle composites[J];Chinese Physics B;2012年11期

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本文編號(hào)：1896297