Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Adsorption of Photoresponsive Surfactants at Solid–Liquid Interfaces
Langmuir ( IF 3.7 ) Pub Date : 2020-11-12 , DOI: 10.1021/acs.langmuir.0c02545 Maren Umlandt 1 , David Feldmann 2 , Emanuel Schneck 3 , Svetlana A. Santer 1 , Marek Bekir 1
Langmuir ( IF 3.7 ) Pub Date : 2020-11-12 , DOI: 10.1021/acs.langmuir.0c02545 Maren Umlandt 1 , David Feldmann 2 , Emanuel Schneck 3 , Svetlana A. Santer 1 , Marek Bekir 1
Affiliation
|
We report on the adsorption kinetics of azobenzene-containing surfactants on solid surfaces of different hydrophobicity. The understanding of this processes is of great importance for many interfacial phenomena that can be actuated and triggered by light, since the surfactant molecules contain a photoresponsive azobenzene group in their hydrophobic tail. Three surfactant types are studied, differing in the spacer connecting the headgroup and the azobenzene unit by between 6 and 10 CH2 groups. Under irradiation with light of a suitable wavelength, the azobenzene undergoes reversible photoisomerization between two states, a nonpolar trans-state and a highly polar cis-state. Consequently, the surfactant molecule changes its hydrophobicity and thus affinity to a surface depending on the photoisomerization state of the azobenzene. The adsorption behavior on hydrophilic (glass) and hydrophobic (TeflonAF) surfaces is analyzed using quartz crystal microbalance with dissipation (QCM-D) and ζ-potential measurements. At equilibrium, the adsorbed surfactant amount is almost twice as large on glass compared to TeflonAF for both isomers. The adsorption rate for the trans-isomers on both surfaces is similar, but the desorption rate of the trans-isomers is faster at the glass–water interface than at the Teflon–water interface. This result demonstrates that the trans-isomers have higher affinity for the glass surface, so the trans-to-cis ratios on glass and TeflonAF are 80/1 and 2/1, respectively, with similar trends for all three surfactant types.
中文翻译：
固液界面对光敏表面活性剂的吸附
我们报告了不同疏水性的固体表面上含偶氮苯的表面活性剂的吸附动力学。对这种方法的理解对于许多可以被光激活和触发的界面现象非常重要，因为表面活性剂分子的疏水尾部含有光响应性偶氮苯基。研究了三种表面活性剂类型，它们在连接头基和偶氮苯单元的间隔基中的差异为6至10个CH 2基团。在适当波长的光照射下，偶氮苯在两个态（非极性反式态和高极性顺式）之间经历可逆的光异构化-州。因此，表面活性剂分子根据偶氮苯的光异构化状态改变其疏水性并因此改变对表面的亲和力。使用带耗散的石英晶体微量天平（QCM-D）和ζ电位测量来分析在亲水（玻璃）和疏水（TeflonAF）表面上的吸附行为。处于平衡状态时，两种异构体在玻璃上的吸附表面活性剂量几乎是TeflonAF的两倍。在两个表面上反式异构体的吸附速率相似，但是反式异构体在玻璃-水界面的解吸速率比在特富龙-水界面的解吸附速率快。该结果表明反式异构体对玻璃表面具有更高的亲和力，因此反式-到-顺式玻璃和TeflonAF比是80/1和2/1，分别与所有三种表面活性剂类型相似的趋势。
更新日期：2020-11-25
中文翻译：
固液界面对光敏表面活性剂的吸附
我们报告了不同疏水性的固体表面上含偶氮苯的表面活性剂的吸附动力学。对这种方法的理解对于许多可以被光激活和触发的界面现象非常重要，因为表面活性剂分子的疏水尾部含有光响应性偶氮苯基。研究了三种表面活性剂类型，它们在连接头基和偶氮苯单元的间隔基中的差异为6至10个CH 2基团。在适当波长的光照射下，偶氮苯在两个态（非极性反式态和高极性顺式）之间经历可逆的光异构化-州。因此，表面活性剂分子根据偶氮苯的光异构化状态改变其疏水性并因此改变对表面的亲和力。使用带耗散的石英晶体微量天平（QCM-D）和ζ电位测量来分析在亲水（玻璃）和疏水（TeflonAF）表面上的吸附行为。处于平衡状态时，两种异构体在玻璃上的吸附表面活性剂量几乎是TeflonAF的两倍。在两个表面上反式异构体的吸附速率相似，但是反式异构体在玻璃-水界面的解吸速率比在特富龙-水界面的解吸附速率快。该结果表明反式异构体对玻璃表面具有更高的亲和力，因此反式-到-顺式玻璃和TeflonAF比是80/1和2/1，分别与所有三种表面活性剂类型相似的趋势。
京公网安备 11010802027423号