纳米SiO2/十二烷基氨基丙酸钠协同稳定的pH响应性Pickering乳状液  

pH-Responsive Pickering Emulsions Stabilized by Silica Nanoparticles in Combination with N-Dodecyl-β-aminopropionate

作　　者：刘凯鸿 林琪[1] 崔正刚[1] 裴晓梅[1] 蒋建中[1] LIU Kaihong LIN Qi cuI Zhenggang PEI Xiaomei JIANG Jianzhong(The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China)

机构地区：[1]江南大学化学与材料工程学院,教育部食品胶体与生物技术重点实验室,无锡214122

出　　处：《高等学校化学学报》2017年第1期85-93,共9页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21573096);中央高校基本科研业务基金(批准号:J USRP51405A)资助~~

摘　　要：用纳米SiO_2颗粒与微量氨基酸型两性表面活性剂十二烷基氨基丙酸钠作复合乳化剂,以正癸烷为油相,制备了pH响应性O/W型Pickering乳状液.室温下该乳状液在pH≤4.0时稳定,在pH≥6.0时不稳定,因此,可以通过改变水相的pH值使乳状液在稳定和破乳之间多次循环.在酸性水介质中,氨基酸型两性表面活性剂分子呈阳离子状态,可通过静电作用吸附到带负电荷的SiO_2颗粒表面,产生原位疏水化作用,使其转变为表面活性颗粒;而在中性和碱性水介质中,氨基酸型两性表面活性剂呈两性或阴离子状态,不能产生原位疏水化作用,因而导致乳状液破乳.相关作用机理通过吸附量、Zeta电位及接触角等实验数据得以论证.该刺激-响应性Pickering乳状液在乳液聚合、油品输送以及燃料生产等领域具有重要的应用价值.pH-responsive Picketing oil-in-water emulsion with n-decane as oil phase was prepared using negatively charged silica nanoparticles in combination with trace amount of amphoteric surfactant, N-dodecyl- β-aminopropionate （DAP） , as stabilizer. The emulsion is stable at pH≤ 4.0 but unstable at pH ≥ 6.0 at ambient temperature, and therefore can be cycled between stable and unstable for many times. In acidic aqueous media the amphoteric surfactant molecules of amino acid type are turned to cationic form and can then adsorb at negatively charged silica nanoparticle surface with head-on configuration via electrostatic interaction, ren- dering particles surface activity by in situ hydrophobization. However in neutral and alkali aqueous media the amphotetic surfactant molecules are turned back to amphoteric or anionic forms which mostly desorb from parti- cles surface, triggering de-hydrophobization of the particles and coalescence of the oil droplets in emulsion. The relative mechanisms are revealed by measurements of adsorption, Zeta potential, as well as contact angles.

关 键 词：pH响应性表面活性颗粒 pH响应性Pickering乳状液 原位疏水化作用 吸附 静电作用 

分 类 号：O647[理学—物理化学]