本文選題：氟化端基 + 聚甲基丙烯酸甲酯��； 參考：《浙江理工大學(xué)》2015年碩士論文

【摘要】：隨著納米材料的快速發(fā)展,納米尺度的聚合物薄膜在光電材料、超薄涂層以及分離膜等領(lǐng)域的應(yīng)用越來越廣泛。聚合物薄膜分子鏈的擴(kuò)散行為影響材料的界面粘附性以及黏彈性等諸多性能,對聚合物薄膜材料的實(shí)際使用有至關(guān)重要的作用。研究聚合物薄膜分子鏈擴(kuò)散行為,不僅可對聚合物納米材料性能調(diào)控提供理論指導(dǎo),而且對于澄清空間受限聚合物分子動(dòng)力學(xué)的微觀機(jī)制具有重要理論意義。近年來,隨著本課題組對含氟聚合物研究的深入,發(fā)現(xiàn)氟化端基標(biāo)記法可以作為聚合物分子鏈運(yùn)動(dòng)行為的研究手段。本論文利用氟化基團(tuán)標(biāo)記聚甲基丙烯酸甲酯分子鏈,構(gòu)建了下層為氟化端基標(biāo)記PMMA(Mn=4kg/mol),上層為未標(biāo)記PMMA(Mn=60~570kg/mol)的雙層膜。利用接觸角、X射線光電子能譜(XPS)等手段監(jiān)測不同溫度下氟化端基標(biāo)記PMMA分子在上層薄膜內(nèi)的遷移時(shí)間,研究了PMMA薄膜的分子擴(kuò)散行為。探討了上層PMMA薄膜厚度、分子量以及溫度對標(biāo)記PMMA分子擴(kuò)散行為的影響。結(jié)果發(fā)現(xiàn):(1)標(biāo)記PMMA擴(kuò)散至上層膜表面所需要時(shí)間t*與上層膜厚度h關(guān)系符合菲克擴(kuò)散方程。通過兩者的關(guān)系(t*~h)可求得PMMA分子鏈的擴(kuò)散系數(shù)D。擴(kuò)散系數(shù)與文獻(xiàn)報(bào)道值基本一致,說明氟化端基標(biāo)記法是研究聚合物擴(kuò)散行為的有效方法。(2)標(biāo)記PMMA分子鏈擴(kuò)散系數(shù)依賴于上層膜厚度。當(dāng)上層PMMA薄膜的厚度小于某一臨界值hup*時(shí),標(biāo)記PMMA分子鏈的擴(kuò)散系數(shù)隨上層薄膜厚度的降低而降低;當(dāng)薄膜厚度減小到另一臨界厚度hlow*時(shí),擴(kuò)散系數(shù)又趨于恒定。PMMA分子鏈纏結(jié)分子量隨薄膜厚度的變化而變化可能是引起擴(kuò)散系數(shù)隨上層膜厚度改變而改變的主要原因。當(dāng)上層膜厚度小于上臨界厚度hup*時(shí),薄膜的纏結(jié)分子量Me隨薄膜厚度降低而減小,導(dǎo)致PMMA分子鏈擴(kuò)散系數(shù)D降低;當(dāng)上層膜厚度降低到下臨界厚度hlow*時(shí),薄膜的纏結(jié)分子量Me不再隨著薄膜厚度的變化而變化,因而PMMA分子鏈的擴(kuò)散系數(shù)D又趨于恒定。(3)當(dāng)上層膜厚度大于上臨界厚度hup*時(shí),擴(kuò)散系數(shù)D與上層膜分子量的關(guān)系為D~M-0.8;當(dāng)上層膜厚度小于下臨界厚度hlow*時(shí),擴(kuò)散系數(shù)D與上層膜分子量的關(guān)系為D~M-0.4;當(dāng)上層膜厚度在hup*與hlow*之間時(shí),擴(kuò)散系數(shù)D與上層膜分子量的關(guān)系為D~M-0.47(上層膜厚度為40nm)。隨著上層膜厚度的減小,擴(kuò)散系數(shù)的厚度依賴性逐漸減弱。此外,發(fā)現(xiàn)下臨界厚度hlow*基本不隨上層膜PMMA分子量的改變而改變。上臨界厚度hup*隨著上層膜分子量的增加而逐漸減小。hup*與上層PMMA分子鏈回轉(zhuǎn)半徑(Rg)呈現(xiàn)-0.62次方標(biāo)度關(guān)系:hup*~Rg-0.62。
[Abstract]:With the rapid development of nanomaterials, nano-scale polymer films are widely used in the fields of optoelectronic materials, ultrathin coatings and separation films. The diffusion behavior of molecular chains in polymer films affects the interfacial adhesion and viscoelasticity of polymer films and plays an important role in the practical use of polymer films. The study of molecular chain diffusion behavior of polymer films can not only provide theoretical guidance for the performance regulation of polymer nanomaterials, but also be of great theoretical significance in clarifying the micro mechanism of molecular dynamics of spatially confined polymers. In recent years, with the further study of fluorinated polymers, we found that fluorinated end group labeling can be used as a means to study the molecular chain movement of polymers. In this paper, the fluorinated groups were used to label the molecular chain of polymethyl methacrylate (PMMA), and a bilayer membrane with a fluorinated end group labeled PMMA (MNO 4 kg / mol) and an unlabeled PMMA (MN 60570 kg / mol) was constructed. The molecular diffusion behavior of PMMA films was studied by means of X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron spectroscopy (XPS), which were used to monitor the migration time of fluorinated end-group labeled PMMA molecules in the upper layer of films at different temperatures. The effects of the thickness, molecular weight and temperature of the upper PMMA film on the diffusion behavior of the labeled PMMA were investigated. The results are as follows: (1) the relationship between the time t * and the thickness h of the PMMA diffusion film accords with the Fick diffusion equation. The diffusion coefficient D of PMMA molecular chain can be obtained by the relationship between them. The diffusion coefficient is basically consistent with the reported values, which indicates that the fluorinated end group labeling method is an effective method for studying the diffusion behavior of polymers. (2) the molecular chain diffusion coefficient of labeled PMMA depends on the film thickness. When the thickness of the upper PMMA film is less than a critical value, the diffusion coefficient of the labeled PMMA molecular chain decreases with the decrease of the thickness of the upper film, and when the thickness of the film decreases to another critical thickness, the diffusion coefficient of the molecular chain decreases. The change of molecular entanglement molecular weight of PMMA molecular chain with film thickness may be the main reason for the change of diffusion coefficient with the change of film thickness. When the upper layer thickness is less than the upper critical thickness, the tangle molecular weight of the film decreases with the decrease of the film thickness, which leads to the decrease of the diffusion coefficient D of PMMA molecular chain, and when the upper layer thickness decreases to the lower critical thickness, the molecular chain diffusion coefficient D decreases. The entangled molecular weight of the film no longer varies with the thickness of the film, so the diffusion coefficient D of the PMMA molecular chain tends to be constant. (3) when the thickness of the upper layer is larger than that of the upper critical thickness, The relationship between the diffusion coefficient D and the molecular weight of the upper layer is DUM-0.8.The relationship between the diffusion coefficient D and the molecular weight of the upper layer is DfM 0.4 when the thickness of the upper layer is less than the lower critical thickness of the film, and when the thickness of the upper layer is between hup* and hlow*, the relationship between the diffusion coefficient D and the molecular weight of the upper layer is DUM-0.4. The relationship between the diffusion coefficient D and the molecular weight of the film is DfM 0.47 (the thickness of the film is 40nm). The thickness dependence of diffusion coefficient decreases with the decrease of the film thickness. In addition, it is found that the lower critical thickness of hlow* basically does not change with the molecular weight of PMMA. The supercritical thickness hup* decreases gradually with the increase of the molecular weight of the upper layer and the radius of gyration (R g) of the upper PMMA molecular chain presents a scale of -0.62 to the power of -0.62.
【學(xué)位授予單位】：浙江理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ317;TB383.2

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 左彪;和頻振動(dòng)光譜（SFG）研究高分子表面松弛行為[D];浙江理工大學(xué);2011年

，

本文編號(hào)：2081361