Krawczyk Joanna, Karasiewicz Joanna, Wojdat Katarzyna
Department of Interfacial Phenomena, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University in Lublin, Maria Curie-Skłodowska Sq. 3, 20-031 Lublin, Poland.
Department of Chemistry and Technology of Silicon Compounds, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8 Street, 61-614 Poznań, Poland.
Int J Mol Sci. 2025 Jun 7;26(12):5472. doi: 10.3390/ijms26125472.
Measurements of the surface tension of aqueous solutions of some trisiloxane surfactants containing various polyether groups (HOL7, HOL9, and HOL12) at 293 K, 303 K, and 313 K were performed. The studied surfactants were synthesized by hydrosilylation reaction and their structural analysis was carried out by the H NMR, C NMR, Si NMR, as well as FT-IR techniques. The thermal stability of HOL7, HOL9, and HOL12, as well as their molecular weight distributions, were also studied. On the basis of the obtained experimental results of the surface tension of aqueous solutions of HOL7, HOL9, and HOL12, the activity of the studied surfactants at the water-air interface was determined and discussed in the light of intermolecular interactions. Using the measured values of the surface tension, the Gibbs surface excess concentration, the area occupied by the surfactant molecule in the adsorption layer, and the standard Gibbs free energy of adsorption of the studied surfactants at the water-air interface were also calculated. Based on the obtained thermodynamic parameters of adsorption of the studied surfactants at the water-air interface, temperature, as well as a number of polyether groups in the hydrophilic part of surfactant, impact on particular surfactant adsorption was deduced. In general, the changes in the standard Gibbs free energy of adsorption of the studied surfactants at the water-air interface indicate that their adsorption tendency decreases with decreasing temperature. In addition, that tendency also diminishes as the number of the polyether groups in the hydrophilic part of the surfactant increases.
在293K、303K和313K温度下，对一些含有不同聚醚基团（HOL7、HOL9和HOL12）的三硅氧烷表面活性剂的水溶液的表面张力进行了测量。所研究的表面活性剂通过硅氢加成反应合成，并通过¹H NMR、¹³C NMR、²⁹Si NMR以及傅里叶变换红外光谱（FT - IR）技术对其结构进行了分析。还研究了HOL7、HOL9和HOL12的热稳定性及其分子量分布。基于所获得的HOL7、HOL9和HOL12水溶液表面张力的实验结果，根据分子间相互作用确定并讨论了所研究表面活性剂在水 - 空气界面的活性。利用表面张力的测量值还计算了吉布斯表面过剩浓度、表面活性剂分子在吸附层中所占的面积以及所研究表面活性剂在水 - 空气界面的标准吉布斯吸附自由能。基于所获得的所研究表面活性剂在水 - 空气界面的吸附热力学参数，推断出温度以及表面活性剂亲水部分中聚醚基团的数量对特定表面活性剂吸附的影响。一般来说，所研究表面活性剂在水 - 空气界面的标准吉布斯吸附自由能的变化表明，它们的吸附倾向随温度降低而降低。此外，随着表面活性剂亲水部分中聚醚基团数量的增加，这种倾向也会减弱。
