本文選題：聚乙二醇 + 摩擦��； 參考：《浙江大學(xué)》2017年碩士論文

【摘要】：聚乙二醇是一種典型的親水抗污材料,具有優(yōu)良的抗蛋白質(zhì)吸附性能。不僅如此,聚乙二醇在水環(huán)境中還表現(xiàn)出的低摩擦特性。相關(guān)研究表明,這一低摩擦特性可能與其表面的水合層密切相關(guān)。由于實(shí)驗(yàn)手段的局限性,目前尚難以直接在微觀(guān)尺度上闡釋聚乙二醇在水中的低摩擦機(jī)理。近年來(lái),分子模擬已愈來(lái)愈成為一種不可或缺的考察微觀(guān)分子相互作用機(jī)理的有效手段。本文將采用全原子分子動(dòng)力學(xué)模擬,以寡聚乙二醇自組裝單分子膜為研究對(duì)象,從聚乙二醇的水合層中分子的結(jié)構(gòu)和動(dòng)態(tài)行為分析該材料的摩擦機(jī)制和特征。此外,本文也考察了電場(chǎng)中水分子的結(jié)構(gòu)及動(dòng)態(tài)響應(yīng)特征,以期為未來(lái)進(jìn)一步研究電控摩擦過(guò)程提供鋪墊。全文主要內(nèi)容和結(jié)論有:1、模擬了不同間距的寡聚乙二醇自組裝單分子膜(OEG-SAM)表面的水潤(rùn)滑摩擦。結(jié)果分析表明,OEG-SAM表面在摩擦過(guò)程中顯著影響了表面上水合層中水分子的動(dòng)態(tài)行為,水合層的水的結(jié)構(gòu)和動(dòng)態(tài)行為與主體水存在差異。表面摩擦系數(shù)與水合層的相互作用關(guān)系密切。當(dāng)表面間距低于15A時(shí),兩表面的水合層直接接觸,摩擦系數(shù)較高。2、模擬了不同溫度下的寡聚乙二醇自組裝單分子膜(OEG-SAM)表面的水潤(rùn)滑摩擦。對(duì)表面水合層的分析表明,溫度280K-310K范圍內(nèi),升高溫度會(huì)導(dǎo)致水合層內(nèi)水分子動(dòng)態(tài)行為的增強(qiáng),水合層的流動(dòng)性增強(qiáng),進(jìn)而導(dǎo)致表面摩擦系數(shù)的降低。3、模擬了水在電場(chǎng)中的行為。結(jié)果表明:外加電場(chǎng)的升高會(huì)導(dǎo)致水的密度上升。與未加電場(chǎng)相比,外加電場(chǎng)強(qiáng)度為1.0V/A時(shí),水的密度上升22%。當(dāng)外加電場(chǎng)為周期性電場(chǎng)時(shí),水的密度也會(huì)以相同的周期實(shí)時(shí)變化。
[Abstract]:Polyethylene glycol (PEG) is a typical hydrophilic antifouling material with excellent protein adsorption resistance. Not only that, polyethylene glycol in the water environment also showed a low friction characteristics. The results show that this low friction property may be closely related to the hydration layer on the surface. Due to the limitation of experimental means, it is difficult to explain the mechanism of low friction of polyethylene glycol in water directly on micro scale. In recent years, molecular simulation has become an indispensable and effective means to study the mechanism of micromolecular interaction. The friction mechanism and characteristics of polyethylene glycol (PEG) self-assembled monolayer films are analyzed from the molecular structure and dynamic behavior in the hydration layer of polyethylene glycol by means of full atomic molecular dynamics simulation. In addition, the structure and dynamic response of water molecules in an electric field are also investigated in order to provide a basis for further study on the electronic friction process in the future. The main contents and conclusions of this paper are as follows: 1. The water lubricated friction on the surface of monolayer OEG-SAM with different spacing is simulated. The results show that the surface of OEG-SAM has a significant effect on the dynamic behavior of water molecules in the hydrated layer during friction, and the water structure and dynamic behavior of the hydrated layer are different from that of the main water. The surface friction coefficient is closely related to the interaction of the hydrated layer. When the surface spacing is lower than 15A, the hydration layer of the two surfaces is in direct contact with a high friction coefficient of 0.2. The water lubricated friction on the surface of the monolayer OEG-SAM is simulated at different temperatures. The analysis of the surface hydration layer shows that in the range of temperature 280K-310K, increasing the temperature will lead to the enhancement of the dynamic behavior of water molecules in the hydration layer and the increase of the fluidity of the hydration layer, which will lead to the decrease of the friction coefficient of the surface. The behavior of water in the electric field is simulated. The results show that the density of water increases with the increase of external electric field. When the applied electric field intensity is 1.0V/A, the water density increases 22% compared with that without electric field. When the applied electric field is a periodic electric field, the density of water will change in real time with the same period.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：O632.3

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本文編號(hào)：1814395