Gao Ming, Wang Xiao-Guang, Lv Wei-Feng, Zhou Zhao-Hui, Zhang Qun, Ma De-Sheng, Wang Hong-Zhuang, Yan Feng, Zhang Lei, Zhang Lu
State Key Laboratory of Enhanced Oil Recovery (PetroChina Research Institute of Petroleum Exploration and Development), Beijing 100083, P. R. China.
Soft Matter. 2020 Jun 21;16(23):5450-5457. doi: 10.1039/d0sm00689k. Epub 2020 Jun 2.
The adsorption and wetting on quartz surfaces by aqueous solutions of xylyl-substituted biquaternary ammonium salt gemini surfactants with different spacer groups (C and C), have been investigated. The interfacial properties of surfactant solutions such as contact angle, adhesional tension (γ cos θ), quartz-water interfacial tension (γ) as well as adhesion work (W) have been estimated. The obtained results show that C and C have similar adsorption behavior on quartz surfaces. Before critical micelle concentration (cmc) is reached, the contact angles of gemini surfactants slowly increase with the increasing concentration, and the adsorption amount at the water-air interface is almost the same as those at a quartz-water interface. After reaching cmc, the gemini surfactant Cn molecules form a more compact adsorption film through bending the flexible spacer chain, instead of forming a bi-layer. As a result, a further increase in quartz-liquid interfacial tension (γ) and a consequent increase in contact angle have been observed after cmc. Gemini C shows a stronger ability towards hydrophobic modification at a quartz surface than C, demonstrating the contribution of the longer methylene spacer to the hydrophobic modification of the quartz surface.
研究了具有不同间隔基团（C和C）的二甲苯基取代双季铵盐双子表面活性剂水溶液在石英表面的吸附和润湿性。估算了表面活性剂溶液的界面性质，如接触角、粘附张力（γ cos θ）、石英-水界面张力（γ）以及粘附功（W）。所得结果表明，C和C在石英表面具有相似的吸附行为。在达到临界胶束浓度（cmc）之前，双子表面活性剂的接触角随浓度增加而缓慢增大，且在水-空气界面的吸附量与在石英-水界面的吸附量几乎相同。达到cmc后，双子表面活性剂Cn分子通过弯曲柔性间隔链形成更致密的吸附膜，而不是形成双层膜。结果，在cmc之后观察到石英-液体界面张力（γ）进一步增大，接触角随之增大。双子表面活性剂C在石英表面的疏水改性能力比C更强，表明较长的亚甲基间隔基团对石英表面疏水改性的贡献。
