脂肪酰基氨基酸表面活性剂亲/疏水基结构对界面性质的影响  

Effect of hydrophilic and hydrophobic groups on interfacial properties of fatty acyl amino acid surfactants

作　　者：李尤 张圆圆 冉朝明 刘畅瑶 王策 徐宝财[1] LI You;ZHANG Yuanyuan;RAN Zhaoming;LIU Changyao;WANG Ce;XU Baocai(School of Light Industry Science and Engineering,Beijing Technology and Business University,Beijing 100048,China)

机构地区：[1]北京工商大学轻工科学与工程学院,北京100048

出　　处：《精细化工》2024年第11期2448-2455,共8页Fine Chemicals

基　　金：国家自然科学基金项目(22008002);北京市属高校教师队伍建设支持计划优秀青年人才项目(BPHR202203049);北京市教委项目(KM202110011001)。

摘　　要：以月桂酸甲酯、肉豆蔻酸甲酯、棕榈酸甲酯分别与丙氨酸、丝氨酸、苏氨酸反应制备了9种脂肪酰基氨基酸表面活性剂。通过表/界面张力测试及界面扩张流变实验,探究了亲/疏水基的协同作用对脂肪酰基氨基酸表面活性剂界面行为的影响。结果表明,与脂肪酰基丙氨酸相比,脂肪酰基丝氨酸和脂肪酰基苏氨酸表面活性剂α取代基中的羟基有助于增强分子间氢键作用、提高界面活性并促进表面活性剂分子在界面上的紧密排列。同时,脂肪酰基碳链长度的增长可使氨基酸α取代基对表面活性剂界面性质的影响更加显著,而氨基酸α极性取代基有利于长链脂肪酰基表面活性剂的亲水亲油平衡,改善其界面性能。由于羟基和长链脂肪酰基的协同增效,棕榈酰基丝氨酸表面活性剂(C16Ser)的临界胶束浓度(CMC)可降至3.9×10^(–4)mol/L,该浓度下的表面张力(γCMC)可降至27.60 mN/m,分子最小截面积低至0.87 nm^(2),界面扩张模量可达47.60 mN/m。脂肪酰基氨基酸表面活性剂的α取代基中的羟基与长脂肪酰基在提高界面性能方面相互配合,呈现出良好的协同效应。Nine kinds of fatty acyl amino acid surfactants were prepared from the reaction of methyl laurate,methyl myristate and methyl palmitate with alanine,serine and threonine,respectively.The effect of the synergistic interaction between hydrophilic/hydrophobic groups on the interfacial behavior of fatty acyl amino acid surfactants were analyzed by surface/interfacial tension test and interfacial dilatational rheological experiments.The results showed that compared with that of fatty acylalanine,the hydroxyl groups inα-substituents of fatty acylserine and fatty acylthreonine surfactants contributed to the enhancement of intermolecular hydrogen bonding,the improvement of interfacial activity,and the close arrangement of surfactant molecules at the interface.Meanwhile,the increase in the fatty acyl carbon chain length made the influence of amino acidα-substituents on the interfacial properties of surfactants more significant.In turn,the polarα-substituent of amino acid facilitated the hydrophilic-lipophilic balance of long-chain fatty acyl surfactants and improved their interfacial properties.Due to the synergistic effect of hydroxyl group and long chain fatty acyl group,the critical micelle concentration(CMC)of palmitoyl serinate surfactant declined to 3.9×10^(–4)mol/L,the surface tension of aqueous solution at CMC was reduced to 27.60 mN/m,the minimum surface area occupied per surfactant molecule at surface decreased to 0.87 nm^(2),and the interfacial dilatational modulus was enhanced as high as to 47.60 mN/m.Hydroxyl group of amino acid and long fatty acyl group showed a good synergistic interaction in the enhancement of interfacial properties.

关 键 词：脂肪酰基氨基酸表面活性剂 丙氨酸 丝氨酸 苏氨酸 界面扩张流变 

分 类 号：TQ423[化学工程]