间隔基含羟基的Gemini表面活性剂在EAN中的聚集行为
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- 英文论文题名：Unique Phase Behaviors in the Gemini Surfactant/EAN Binary System:the Role of the Hydroxyl Group
- 论文作者：李钦堂 ; 陈晓
- 英文论文作者：Qintang Li ; Xiao Chen ; Key Laboratory of Colloid and Interface Chemistry ; Shandong University ; Ministry of Education
- 年：2016
- 作者机构：山东大学胶体与界面化学教育部重点实验室;
- 论文关键词：Gemini表面活性剂 ; 羟基 ; 离子液体 ; 双液相
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第三十一分会：胶体与界面化学
- 语种：中文
- 分类号：O647.2
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第三十一分会 ; 胶体与界面化学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：198k
- 原文格式：D
- 会议级别：全国
摘要
本文研究了间隔基含羟基基团的Gemini表面活性剂12-3OH-12在质子化离子液体硝酸乙基铵(EAN)中聚集行为。表面张力的结果表明,随着羟基的引入,12-3OH-12的临界胶束浓度低于不含羟基的同系分子12-3-12,且12-3OH-12在气/液界面排列更加紧密,这可能源于12-3OH-12与EAN间的氢键作用。在12-3OH-12/EAN体系中,能够在很宽浓度和温度区间内观察到胶束相分离为两相的现象。通过小角X射线散射和冷冻刻蚀电子显微镜观察,上相为密堆积的胶束溶液,而下相是稀的胶束溶液。12-3OH-12/EAN体系先后出现反六角相和反双连续立方相,而12-3-12只能形成反六角相,这也验证了12-3OH-12具有更小的分子头基占据面积。但12-3OH-12所形成反六角相具有较差的粘弹性和热稳定性。这些独特的聚集行为是由于12-3OH-12较强的亲溶剂作用及EAN相对较弱的组装促进能力所致。
The hydroxyl group in the spacer of a cationic Gemini surfactant(12-3OH-12) caused dramatic phase behavior changes in a protic ionic liquid,ethylammonium nitrate(EAN),compared to the homologue Gemini molecule without hydroxyl(12-3-12).Here,the effects of the hydroxyl group on micellization and lyotropic liquid crystal formation were investigated through the surface tension,small-angle X-ray scattering,polarized optical microscopy,and rheological measurements.The critical micellization concentration of 12-3OH-12 was found to be lower than that of 12-3-12 and the 12-3OH-12 molecules packed more densely at the air/EAN interface.At wide concentration and temperature ranges,an interesting coexistence of two separated phases was observed in12-3OH-12/EAN system,as shown in Fig.1.Such a micellar phase separation was rarely observed in the ionic surfactant and ionic liquid binary systems.With the further increase of surfactant concentration,the reverse hexagonal and bicontinuous cubic phases appeared in sequence,whereas only a reverse hexagonal phase was found in 12-3-12/EAN system.The hexagonal phase formed with 12-3OH-12 exhibited lower viscoelasticity and thermostability than those observed in 12-3-12/EAN system.Such unique changes in phase behaviors of12-3OH-12 were ascribed to their enhanced solvophilic interactions of 12-3OH-12 and relatively weak solvophobic interactions in EAN.
The hydroxyl group in the spacer of a cationic Gemini surfactant(12-3OH-12) caused dramatic phase behavior changes in a protic ionic liquid,ethylammonium nitrate(EAN),compared to the homologue Gemini molecule without hydroxyl(12-3-12).Here,the effects of the hydroxyl group on micellization and lyotropic liquid crystal formation were investigated through the surface tension,small-angle X-ray scattering,polarized optical microscopy,and rheological measurements.The critical micellization concentration of 12-3OH-12 was found to be lower than that of 12-3-12 and the 12-3OH-12 molecules packed more densely at the air/EAN interface.At wide concentration and temperature ranges,an interesting coexistence of two separated phases was observed in12-3OH-12/EAN system,as shown in Fig.1.Such a micellar phase separation was rarely observed in the ionic surfactant and ionic liquid binary systems.With the further increase of surfactant concentration,the reverse hexagonal and bicontinuous cubic phases appeared in sequence,whereas only a reverse hexagonal phase was found in 12-3-12/EAN system.The hexagonal phase formed with 12-3OH-12 exhibited lower viscoelasticity and thermostability than those observed in 12-3-12/EAN system.Such unique changes in phase behaviors of12-3OH-12 were ascribed to their enhanced solvophilic interactions of 12-3OH-12 and relatively weak solvophobic interactions in EAN.
引文
Li,Q.T.;Wang,X.D.;Yue,X.;Chen,X.Langmuir,2015,31,13511-13518.