摘要
采用双甘肽对β-谷甾醇进行改性,合成了一种植物甾醇基寡肽型表面活性剂——谷甾醇甲酰基双甘肽钾(Sito-GG)。采用1HNMR和MS对其进行了表征,利用表/界面张力测试及界面扩张流变实验,探究了其界面自组装行为。结果表明,Sito-GG的临界胶束浓度(CMC)为5.75×10^(-5) mol/L,在CMC下的表面张力为30.95 mN/m,饱和吸附量为4.07×10^(-10) mol/cm^(2),分子最小截面积0.40 nm^(2),呈现出良好的界面活性。Sito-GG中较大的刚性甾体结构赋予了疏水基间较强的范德华力,双甘肽的多个酰胺基团增强了亲水基之间的氢键作用,两者共同促进了Sito-GG分子在界面上的紧密排列,并明显抑制了界面弛豫过程。Sito-GG的界面扩张弹性模量和黏性模量在测试频率(0.005~0.1 Hz)范围内几乎不随频率发生变化,当其浓度为2×10^(-4) mol/L时,界面扩张模量可达165 mN/m,黏性模量最大值仅约为10 mN/m,形成了具有较高强度的界面膜,呈现出典型的弹性膜特点。
A phytosterol-oligopeptide surfactant,sitosteryl-glycylglycine potassium(Sito-GG),was synthesized via modification onβ-sitosterol with glyglycine,characterized by^(1)HNMR and MS,and analyzed by surface/interfacial tension tests and interfacial dilatational rheological experiments for its interfacial self-assembly behavior.The results showed that the surfactant exhibited excellent interfacial activity,with a critical micelle concentration(CMC)of 5.75×10^(-5) mol/L,a surface tension at CMC of 30.95 mN/m,a saturation adsorption capacity of 4.07×10^(-10) mol/cm^(2),and the minimum molecular cross-sectional area of 0.40 nm^(2).The large rigid sterol structure of Sito-GG endowed the molecules with strong van der Waals forces,while the multiple amide groups of glyglycol enhanced the hydrogen bonding between hydrophilic groups.Both interactions promoted the close rearrangement of Sito-GG molecules at the interface and significantly inhibited the relaxation processes.The interfacial dilational elastic modulus and viscoelastic modulus of Sito-GG remained almost unchanged within the tested frequency range(0.005~0.1 Hz).When the concentration of Sito-GG was 2×10^(-4) mol/L,the interfacial dilational modulus reached as high as 165 mN/m,the maximum value of viscous modulus was about 10 mN/m,indicating the formation of an interfacial film with high strength.
作者
冉朝明
王娜
张平平
赵莉
徐宝财
王策
RAN Zhaoming;WANG Na;ZHANG Pingping;ZHAO Li;XU Baocai;WANG Ce(School of Light Industry Science and Engineering,Beijing Technology and Business University,Beijing 100048,China)
出处
《精细化工》
北大核心
2026年第3期596-602,共7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)。
关键词
谷甾醇
双甘肽
界面自组装
界面扩张流变
表面活性剂
sitosterol
glyglycine
interfacial self-assembly
interfacial dilatational rheology
surfactants
