Anion Effect on the Tunable Stability of a Thermoresponsive Pickering Emulsion Based on SiO2-PNIPAM

Fang CHEN, 西北工业大学理学院, 空间应用物理与化学教育部重点实验室, 陕西省高分子科学与技术重点实验室, 西安 710129, 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, Zhu-Guo CHEN, Hui-Zhao SUN, Fan-Xiang MENG, Xiao-Yan MA
2016 Wuli huaxue xuebao  
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
more » ... nalyzed by dynamic light scattering (DLS), and its lower critical solution temperature (LCST) is 30 °C. 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 °C. 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.
doi:10.3866/pku.whxb201512111 fatcat:4zznetuvpreh3ivlyp6erpc7pm