Poly(ionic Liquid)-based Responsive Nanogel Prepared By Ternary Cross-linking Copolymerization

Stimulus responsive polymer is a polymer which can respond quickly to small stimuli in external environment with mutations in the structures, physical and chemical properties at the same time. And it can response to the stimulation of specific signals for identification or achieve chain conformation and present the phase transition behavior in particular external environment. Stimulus responsive polymer is various in responds to temperature, p H, ionic strength, light, magnetic field, electric field, ultrasound, redox/thiol, etc. Especially, stimuli-responsive polymers of reversibility and biological compatibility are very appealing and important, which have been used in drug controlled release, separation extraction, tissue engineering and other areas. Therefore, it has very important theoretical significance and application value to design and prepare novel stimuli-responsive polymer.In our previous study, we found that the introduction of hydrogen bond interactions into nanogels can produce novel thermosensitive polymer materials.Based on this founding, we herein prepared functional poly(ionic liquid)-based thermosensitive nanogel by ternary cross-linking polymerization. Due to the introduction of functional ionic liquid, the novel PIL-based nanogels presented reversible temperature-responsive. The formation mechanism of PIL-based thermosensitive nanogel prepared by ternary cross-linking polymerization and the relationship between the different polymerization conditions with thermosensitive nanogel were investigated. The responsive behaviors and properties were detailedly characterized.Supramolecular chemistry is one of the most popular fields nowadays, especially molecular recognition and self-assembly. The host-guest interactions contain ion-dipole interaction, dipole-dipole interaction, hydrogen bonding interaction,cation-π interaction, π-π interaction and so on. Studied on supramolecular chemistry were most between macromolecule or polymer and host molecular.In this study, we fabricated a novel guest molecular belong to polymer nanogel.Due to the interactions between host and guest, we achieve the goal that it is successful to introduce host-guest interactions into polymer nanogels.The main contents include the following:1. Preparation of the ionic liquid monomers which have different compositions and structures, including: 1- vinyl- 3- carboxymethylimidazole chloride ionic liquid,1- vinyl- 3- hydroxyethylimidazole bromine ionic liquid,(4-vinylbenzyl-triphenyl phosphorous chloride ionic liquid, 3-(4-vinyl benzyl)-1-vinylimidazolium chloride ionic liquid, and these were characterized using 1H-NMR, 13C-NMR and melting point.2. Preparation of poly(ionic liquid)-based stimuli-responsive nanogels, via one-step synthesis poly(ionic liquid)-based nanogel by ternary cross-linking polymerization. The results illustrated that the nanogel can form stable macro gel in the lower temperature, and the change was a reversible process, while using the free functional ionic liquids, the nanogel had no thermosensitivity. Therefore, it was an effective way that poly(ionic liquid)-based thermosensitive nanogel was prepared by introduced carboxyl and hydroxy. The nanogels were characterized using FT-IR, TG,SEM, DLC, UV-vis, and the responsive mechanism of nanogels was discussed.3. Preparation of supramolecular polymer via π-π interactions and charge transfer interactions: the host which was prepared according to references was characterized using 1H-NMR; one of the guests was prepared via one-step synthesis poly(ionic liquid)-based nanogel by ternary cross-linking polymerization, the other was prepared according to references. The supramolecular polymer were characterized using 1H NMR、DLC、SEM, and the influence of different rate of feed on supramolecular polymer was discussed.