Ren Gaihuan, Li Bo, Ren Lulu, Di Wenwen, Tian Lulu, Zhang Pan, Shao Weili, He Jianxin, Sun Dejun
Textile and Garment Industry of Research Institute, Zhongyuan University of Technology, Zhengzhou, Henan 450007, P. R. China.
Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan, Shandong 250100, P. R. China.
Langmuir. 2021 Jun 8;37(22):6632-6640. doi: 10.1021/acs.langmuir.1c00097. Epub 2021 May 27.
Acid-responsive nonaqueous (glycerol in -decane) Pickering emulsions were prepared using preferentially oil-wetted dynamic covalent silica (SiO-pDB) nanoparticles as the Pickering emulsifiers. The acid-responsive Pickering emulsifier SiO-pDB was prepared based on a Schiff base reaction between amino silica (SiO-NH) and -decanoxybenzaldehyde (pDBA). The formation of SiO-pDB was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis. The preferentially oil-wetted character of SiO-pDB was indicated by contact angle measurement. Stable nonaqueous Pickering emulsions were prepared using preferentially oil-wetted SiO-pDB as the Pickering emulsifier. However, after adjusting the nonaqueous Pickering emulsions to an acidic environment, complete phase separation occurred. In the acidic environment, preferentially oil-wetted SiO-pDB decomposed into hydrophilic SiO-NH and hydrophobic pDBA due to the decomposition of the dynamic imine bond in the SiO-pDB. Then, the hydrophilic SiO-NH and hydrophobic pDBA desorbed from the two-phase interface, resulting in complete phase separation of the initially stable nonaqueous Pickering emulsions. The acid-responsive nonaqueous Pickering emulsions show great potential in application in water sensitive systems, such as oil-based drilling fluids.
使用优先被油润湿的动态共价二氧化硅（SiO-pDB）纳米颗粒作为皮克林乳化剂，制备了酸响应性非水（癸烷中的甘油）皮克林乳液。酸响应性皮克林乳化剂SiO-pDB是基于氨基二氧化硅（SiO-NH）与癸氧基苯甲醛（pDBA）之间的席夫碱反应制备的。通过傅里叶变换红外光谱、热重分析和元素分析对SiO-pDB的形成进行了表征。通过接触角测量表明了SiO-pDB优先被油润湿的特性。使用优先被油润湿的SiO-pDB作为皮克林乳化剂制备了稳定的非水皮克林乳液。然而，将非水皮克林乳液调节至酸性环境后，发生了完全相分离。在酸性环境中，由于SiO-pDB中动态亚胺键的分解，优先被油润湿的SiO-pDB分解为亲水性的SiO-NH和疏水性的pDBA。然后，亲水性的SiO-NH和疏水性的pDBA从两相界面解吸，导致最初稳定的非水皮克林乳液完全相分离。酸响应性非水皮克林乳液在水敏系统（如油基钻井液）中的应用显示出巨大潜力。
