the National Natural Science Foundation of China(51103117);Natural Science Foundation of Shaanxi Province, China(2013JQ2010, 2013/M2012);NPU Foundations for Fundamental Research, China(3102014JCQ01089)
Anion Effect on the Tunable Stability of a Thermoresponsive Pickering Emulsion Based on SiO2-PNIPAM
Fang CHEN,Zhu-Guo CHEN,Hui-Zhao SUN,Fan-Xiang MENG,Xiao-Yan MA. Anion Effect on the Tunable Stability of a Thermoresponsive Pickering Emulsion Based on SiO2-PNIPAM[J]. Acta Physico-Chimica Sinica, 2016, 32(3): 763-770. DOI: 10.3866/PKU.WHXB201512111
The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, The Key Laboratory of Polymer Science and Technology of Shaanxi Province, School of Science, Northwestern Polytechnical University, Xi'an 710129, P. R. China
Abstract:
Thermoresponsive hybrid particles of SiO2-PNIPAM (PNIPAM: poly(N-isopropyl acrylamide) were synthesized by surface initiated atom transfer radical polymerization (SI-ATRP). The structure of hybrid particles was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The grafting ratio of PNIPAM on the silica surface was about 103.7%as measured by thermogravimetric analysis (TGA). The thermoresponsive behavior of monodisperse hybrid particles was analyzed by dynamic light scattering (DLS), and its lower critical solution temperature (LCST) is 30 ℃. The influence of anions on the wettability of hybrid particles was studied by measuring the surface contact angle. A large stability difference of the emulsion based on SiO2-PNIPAM exists between 40 and 10 ℃. The degree of flocculation of hybrid particles shows a significant influence on the stability of the emulsion. The emulsion stability is dependent on the electrostatic interaction and salting out caused by the solvation effect. This stability is tunable by introducing different anions at different concentrations.
