ИСТИНА

In recent years, polymer microgels, especially thermo- and pH-sensitive, attracted the interest of researchers. First of all, this is due to the unique properties of these objects: on the one hand, microgels are able to form a stable to aggregation dispersions. On the other, they are a sufficiently well characterized microscopic object whose size and properties can be governed by changing the external conditions. The creation of microgels with nonuniform inner structure and developing ways to control it can open new opportunities for their practical use. In our group it was theoretically predicted that shell–corona structure could be formed in the case of interpenetrated microgel particles (IPN microgels) by a pair of initially interpenetrated collapsed and swollen networks [1]. The main objective of the presented work is to obtain the thermo- and pH- sensitive microgels based on two interpenetrating networks, to study their properties and check the possibility to use them for the development of stimuli-responsive polymer films and coatings. One of the advantages of using microgels instead of macrogels - it can give additional opportunities for managing the internal structure and mechanical properties of the material. The synthetic strategy of the development of IPN microgels on the basis of environment sensitive interpenetrating networks of poly(N-isopropylacrylamide) (PNIPAM) and poly(acrylic acid) (PAA) was elaborated. IPN microgels were synthesized by in situ polymerization of acrylic acid within PNIPAM microgel particles obtained by thermo-induced precipitation polymerization. Different types of cross-linking agents and cross-linking mechanisms were used to govern the network topology both for NIPAM and AA component. Polymer films were developed by assembling of IPN gel particles. In some cases, polymer films were additionally crosslinked by multivalent ions and reduction-oxidation treatment. Inner structure and thermo- and pH- induced swelling behavior of obtained gel particles and materials was investigated.