Influence of immobilized cations on the thermodynamic signature of hydrophobic interactions at chemically heterogeneous surfaces
Influence of immobilized cations on the thermodynamic signature of hydrophobic interactions at chemically heterogeneous surfaces
复制标题
固定阳离子对化学异质表面疏水相互作用热力学特征的影响
DOI：
10.1039/d0me00016g
复制
发表时间：
2020
影响因子：
3.6
通讯作者：
Abbott, Nicholas L.
中科院分区：
文献类型：
--
作者：
Yeon, Hongseung;Wang, Chenxuan;Gellman, Samuel H.;Abbott, Nicholas L.
疏水相互作用在水中分子自组装的生物启发策略中发挥着核心作用，但这些相互作用如何由化学异质界面编码却知之甚少。我们报告了固定化的极性基团（胺）和阳离子（铵和胍）的影响的实验研究，在温度范围从298 K至328 K和pH值3.5至10.5之间的甲基封端的表面介导的疏水相互作用的疏水和熵的贡献。我们使用我们的测量来计算伴随每个表面从含有60体积%甲醇的水性TEA转移到水性TEA（即，传递表征疏水性的自由能）。我们发现纯甲基表面的热力学签名（正转移焓和熵）被定性地改变，通过将胺或胍基团并入表面（负转移焓和近零转移熵）。相反，固定在甲基表面上的铵基团不改变疏水相互作用的热力学特征。熵和焓的补偿在我们的结果中是明显的，但在转移自由能的总体趋势是由双折射效应主导的。这一观察和其他人导致我们假设，在我们的实验中，固定化的带电或极性基团的主导作用是影响相邻的非极性域的界面水分子形成的氢键的数量或强度。总的来说，这些结果提供了深入了解化学异质表面的熵-焓补偿，并生成假设和丰富的实验数据集，通过模拟进行进一步探索。
Hydrophobic interactions play a central role in bioinspired strategies for molecular self-assembly in water, yet how these interactions are encoded by chemically heterogeneous interfaces is poorly understood. We report an experimental investigation of the influence of immobilized polar groups (amine) and cations (ammonium and guanidinium) on enthalpic and entropic contributions to hydrophobic interactions mediated by methyl-terminated surfaces at temperatures ranging from 298 K to 328 K and pH values between 3.5 to 10.5. We use our measurements to calculate the change in free energy (and enthalpic and entropic components) that accompanies transfer of each surface from aqueous TEA containing 60 vol% methanol into aqueous TEA (i.e., transfer free energy that characterizes hydrophobicity). We find the thermodynamic signature of the pure methyl surface (positive transfer enthalpy and entropy) to be altered qualitatively by incorporation of amine or guanidinium groups into the surface (negative transfer enthalpy and near zero transfer entropy). In contrast, ammonium groups immobilized on a methyl surface do not change the thermodynamic signature of the hydrophobic interaction. Compensation of entropy and enthalpy is clearly evident in our results, but the overall trends in the transfer free energies are dominated by enthalpic effects. This observation and others lead us to hypothesize that the dominant effect of the immobilized charged or polar groups in our experiments is to influence the number or strength of hydrogen bonds formed by interfacial water molecules adjacent to the nonpolar domains. Overall, these results provide insight into entropy–enthalpy compensation at chemically heterogeneous surfaces, and generate hypotheses and a rich experimental dataset for further exploration via simulation.
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影响因子：
3.3
作者：
Florián, J;Warshel, A
通讯作者：
Warshel, A
非共沸二元混合物沸点曲线的室内实验
DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
G. W. Bennett
通讯作者：
G. W. Bennett
影响因子：
3.3
作者：
Florian, J;Warshel, A
通讯作者：
Warshel, A
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影响因子：
3.2
作者：
H. Wincel
通讯作者：
H. Wincel
烷基胺及其相应质子化形式的水合行为。
影响因子：
2.9
作者：
Holger Hesske;K. Gloe
通讯作者：
K. Gloe