本文選題：高分子 + 吸附�。� 參考：《浙江大學(xué)》2017年博士論文

【摘要】：高分子在表面的吸附是生物、物理和化學(xué)領(lǐng)域的重要課題,這歸因于它的普遍性和巨大的潛在應(yīng)用價(jià)值,如高分子粘合劑、膠體穩(wěn)定化、高分子納米復(fù)合材料、涂層和潤滑、細(xì)菌內(nèi)DNA的分離、病毒內(nèi)DNA的包裝和超疏水/超親水材料。我們用Monte Carlo方法研究了高分子在吸引表面上的吸附、構(gòu)象和動(dòng)力學(xué)性質(zhì)。主要的研究內(nèi)容和結(jié)果如下:(1)高分子在均勻吸引表面上的吸附過程。在吸附過程中高分子鏈平行于表面的表觀尺寸隨著時(shí)間指數(shù)增加。達(dá)到它的平衡值所需的弛豫時(shí)間隨表面吸引強(qiáng)度EPS的增加而減小,但平衡值隨EPs增加,這表明強(qiáng)吸引時(shí)高分子吸附得更快,且更加擴(kuò)展。高分子平行于表面的非球形因子在吸附過程中表現(xiàn)的行為與表觀尺寸不同,對高分子鏈內(nèi)部相互作用較敏感。在吸附過程中,表面接觸鏈節(jié)數(shù)隨著時(shí)間單調(diào)增加,但是高分子三維構(gòu)象尺寸和形狀非球形因子表現(xiàn)出新奇的行為。隨著表面接觸鏈節(jié)數(shù)的增加,它們先增加,然后減小,最后又增加。而二維構(gòu)象尺寸和形狀非球形因子隨著表面接觸鏈節(jié)數(shù)的增加先減小,然后增加。(2)吸附在均勻表面上的高分子的塌縮相變,研究了表面吸引強(qiáng)度EPS和鏈內(nèi)吸引強(qiáng)度EPP對高分子相的影響。塌縮相變點(diǎn)和EPs有關(guān),高分子構(gòu)象和EPP、EPS有關(guān)。EPS小時(shí),吸附鏈的構(gòu)象是三維層狀結(jié)構(gòu)。EPs大時(shí),EPP = 0的構(gòu)象幾乎是二維的,我們觀察到二維塌縮相變和從二維構(gòu)象到三維層結(jié)構(gòu)的形成層相變,形成層相變點(diǎn)隨著EPS的增加而增加。另外,我們發(fā)現(xiàn)吸附壓制塌縮相變,也就是說,塌縮相變點(diǎn)隨著EPS的增加而增加。(3)吸附在均勻吸引表面上的高分子鏈的動(dòng)力學(xué)行為。平行于表面的平動(dòng)擴(kuò)散系數(shù)Dxy隨著鏈內(nèi)吸引強(qiáng)度EPP或表面吸引強(qiáng)度EPS的增加而減小。轉(zhuǎn)動(dòng)弛豫時(shí)間τR隨著EPS的增加而增加,但是對EPP的依賴性和高分子的吸附狀態(tài)有關(guān)。部分吸附鏈的轉(zhuǎn)動(dòng)弛豫時(shí)間隨著EPP的增加而減小,但是完全吸附鏈的轉(zhuǎn)動(dòng)弛豫時(shí)間隨著EPP的增加而增加。對于長鏈,標(biāo)度關(guān)系Dxy～N-α和τR～N-β均成立。標(biāo)度指數(shù)α和EPS無關(guān),但隨著EPP的增加而增加,EPP = 0時(shí),α= 1.06。EPP = 0時(shí),吸附鏈的β≈2.7,幾乎和EPS無關(guān)。但EPP0時(shí),β隨著EPs的增加而增加。而且,我們發(fā)現(xiàn)β總是隨著EPP的增加而減小。我們的結(jié)果揭示了吸引表面對吸附鏈的擴(kuò)散和轉(zhuǎn)動(dòng)的不同影響。(4)隨機(jī)吸引平面上高分子的吸附過程。臨界吸附點(diǎn)分?jǐn)?shù)隨著表面吸引強(qiáng)度和鏈內(nèi)吸引強(qiáng)度EPP的增加而減小。當(dāng)表面吸引強(qiáng)度較大時(shí),高分子平行于表面的表觀尺寸的平衡值隨著吸附點(diǎn)分?jǐn)?shù)的增加先增加后減小。高分子的吸附時(shí)間隨著表面吸引強(qiáng)度的增加而減小,但是隨著EPP的增加而增加。另外,隨機(jī)分布的吸附點(diǎn)使吸附鏈的平動(dòng)擴(kuò)散減慢。
[Abstract]:The adsorption of polymers on the surface is an important subject in the biological, physical and chemical fields. This is due to its universality and potential applications, such as polymer adhesives, colloid stabilization, polymer nanocomposites, coatings and lubrication. Isolation of DNA in bacteria, packaging of DNA in viruses and superhydrophobic / superhydrophilic materials. The adsorption, conformation and kinetic properties of polymers on attractive surfaces have been studied by Monte Carlo method. The main contents and results are as follows: 1) the adsorption process of the polymer on the homogeneous attractive surface. The apparent size of the polymer chain parallel to the surface increases with the time exponent during the adsorption process. The relaxation time required to reach its equilibrium value decreases with the increase of the surface attraction strength EPS, but the equilibrium value increases with the increase of the EPs value, which indicates that the polymer adsorbs more rapidly and expands with the strong attraction. The adsorption behavior of non-spherical factors parallel to the surface of polymers is different from that of the surface, and they are more sensitive to the internal interaction of polymer chains. In the process of adsorption, the number of surface contact chains increases monotonously with time, but the three-dimensional conformational size and shape non-spherical factors of polymer exhibit novel behavior. With the increase of the number of surface contact chains, they first increase, then decrease, and finally increase. However, with the increase of the number of contact chains on the surface, the two-dimensional conformational size and shape non-spherical factors decrease firstly, and then increase .t2) the collapse phase transition of the polymer adsorbed on the uniform surface. The effects of surface attraction strength (EPS) and intrachain attraction strength (EPP) on polymer phase were studied. The collapse phase transition point is related to EPs, and the conformation of macromolecule is related to EPPP-EPS. The conformation of adsorption chain is three-dimensional layer structure. EPS = 0 is almost two dimensional conformation. We observed the collapse phase transition in two dimensions and the cambium phase transition from two dimensional conformation to three dimensional layer structure. The phase transition point of cambium increases with the increase of EPS. In addition, we find that adsorption suppresses the collapse phase transition, that is, the kinetic behavior of the polymer chain adsorbed on the homogeneous attractive surface increases with the increase of EPS. The translational diffusion coefficient (Dxy), which is parallel to the surface, decreases with the increase of the intrachain attraction strength (EPP) or the surface attraction intensity (EPS). The rotational relaxation time 蟿 R increases with the increase of EPS, but the dependence on EPP is related to the adsorption state of polymer. The rotational relaxation time of partial adsorption chain decreases with the increase of EPP, but the rotational relaxation time of fully adsorbed chain increases with the increase of EPP. For long chains, the scale relationship Dxyn- 偽 and 蟿 RN- 尾 hold. The scale exponent 偽 is independent of EPS, but with the increase of EPP, the adsorption chain 尾 鈮，

本文編號(hào)：1887464