分会

第三十五分会：胶体与界面化学

摘要

采用实验和分子动力学(MD)模拟相结合的方法研究了脱氧胆酸钠(NaDC)和反式-邻甲氧基肉桂酸钠(trans-NaOMCA)复配系统在水中的多刺激响应行为。考察了多种外部刺激对NaDC/trans-NaOMCA复配系统的相行为、流变性质和微观结构的影响，测定了施加各种刺激前后复配系统的FT-IR和1H-NMR谱图，并从分子水平上对其多刺激响应机理进行了探讨。实验结果表明，该复配系统表现出良好的pH和CO2/N2循环响应性，293.15 K时在7.43-7.05的较窄pH范围内实现了溶液状态和凝胶状态的可逆转换，剪切粘度变化了5个数量级。此外，将293.15 K下pH = 7.05的凝胶样品升温到305.65 K或紫外光照40 min，剪切粘度可下降3个数量级，实现了凝胶向溶胶的转变。MD模拟结果表明，桥联氢键、疏水作用和静电相互作用在各种刺激诱导的自组装过程中起着关键作用。由于多刺激响应型胶束系统可以通过多元化的参数实现更丰富的调控，因此对复杂的外部环境具有更好的适应性，有助于拓展其应用范围。 The multi-stimuli responsive behaviors of sodium deoxycholate (NaDC) and sodium trans-ortho-methoxycinnamate (trans-NaOMCA) mixed systems in water have been investigated by combining experiments and molecular dynamics (MD) simulations. The effects of various external stimuli on the phase behaviors, rheological properties and microstructures of the NaDC/ trans-NaOMCA mixed systems have been explored. The FT-IR and 1H-NMR spectra of the mixed systems before and after applying various stimulus were measured, and the multi-stimuli responsive mechanism was discussed at the molecular level. The experimental results illustrate that the mixed systems show excellent recycled pH and CO2/N2 response, and the reversible switching between solution state and gel state with 5 orders of magnitude variation in shear viscosity has been achieved within a narrow pH range of 7.43-7.05 at 293.15K. Furthermore, when the gel sample with pH = 7.05 and T = 293.15 K was heated to 305.65 K or UV-irradiated for 40 min, the gel-to-sol transition with 3 orders of magnitude reduction in shear viscosity could be achieved. MD simulation results reveal that the bridging hydrogen bonds, hydrophobic interaction and electrostatic interactions play important roles in the various stimuli-induced self-assembly morphology transitions. Since multi-stimuli responsive micellar systems can be regulated through multiple parameters, resulting in their better adaptability to complex external environments, which is helpful to expand the scope of their application.

关键词

多刺激响应;脱氧胆酸钠;反式-邻甲氧基肉桂酸钠;自组装;分子动力学模拟

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