https://scholars.lib.ntu.edu.tw/handle/123456789/64452
標題: | 穿越奈米孔洞高分子動態行為之研究(2/3) Effect of solvent quality on the conformations of a model comb polymer(2/3) |
作者: | 諶玉真 | 關鍵字: | Monte Carlo simulations;comb polymers;second virial coefficient;structural factor | 公開日期: | 17-五月-2004 | 出版社: | 臺北市:國立臺灣大學化學工程學系暨研究所 | 摘要: | The effect of solvent quality on the equilibrium structure of a densely-branched comb polymer is investigated based on the structure factor analyses by off-lattice Monte Carlo simulations. Firstly, theta temperature ( θ∞) must be determined to identify the solvent condition. We locate the characteristic temperature, θ A,(N), at which the second virial coefficient vanishes and the transition temperature, θ R(N), at which radius of gyration, Rg, of the chain varies most rapidly with temperature, i.e. 0 / 2 2 = R dT R d g θ . N represents the total number of monomers of a comb. As N ∞, θ A and θ R coincide to a point that is identified as the true theta temperature ( θ∞). The structure factors of the main chain, the side chain, and the whole polymer are calculated, respectively. It is found that at T= θ∞, the structural factors S(qRg) for the overall comb polymers match quite well with those of their Gaussian counterparts. When T< θ∞, the overall comb polymer assumes collapsed conformations, similar to a homogeneous sphere. However, the structure factor of the side chain indicates that it always remains in an expanded state regardless of the solvent condition. It is attributed to the strong interactions between side chains. The same effect leads to enhanced rigidity of the main chain in comparison to the linear chain, as clearly observed from the rescaled Kratky plot |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/9370 | 其他識別: | 922214E002003 | Rights: | 國立臺灣大學化學工程學系暨研究所 |
顯示於: | 化學工程學系 |
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922214E002003.pdf | 144.99 kB | Adobe PDF | 檢視/開啟 |
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