Electrical Properties and Stability of Poly(N-isopropylacylamide-co-methacrylic Acid) Core-Shell Microgel

Abstract

Graphical Abstract: A doubly responsive microgel with core shell shape was prepared by seed polymerization. The electrical properties were characterized. The latex stability was evaluated and discussed according to the colloid theory.

A core-shell microgel of poly(N-isopropylacylamide-co-methacrylic acid) was prepared by seeded polymerization. Dynamic light scattering measurements indicated that the microgel had a narrow size distribution. Zeta potential decreased gradually with increasing ionic strength, and when salinity reached a certain concentration the surface charge was almost screened out. Further addition of salt led to the shrinking and final flocculation. For increasing temperature, the zeta potential under higher ionic strength exhibited an abrupt change for trending to zero. Total interaction energy between particles was calculated with colloid theory. Meanwhile, thermal stability was evaluated and interpreted the experimental phenomenons.

Keywords:

• Core-shell microgel
• N-isopropylacylamide
• stability

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (No. 20606010, 20490204), the Doctoral Research Foundation sponsored by the Ministry of Education of China (Project No. 20050251004) and Shanghai Institute of Technology (No. KJ2008-09).