Preparation Of Poly(ionic Liquids) Functional Gels Controlled By Host-guest Interaction With β-cyclodextrin

Host-guest recognition refers to the formation of supramolecular inclusion complexes consisting of two or more entities connected together via noncovalent interactions in a highly controlled and cooperative manner. By changing the physical and chemical properties of guest molecules, such as: water solubility, toxicity, spectroscopic properties, stability, targeting, etc. dissociation and reassembly of the host-guest inclusion complexes would be realized. Ionic liquids(ILs) are organic salts at room temperature which are entirely composed of anion and cation. They have unique properties, such as low volatility, excellent chemical stability, and high thermal stability.The supramolecular gels show designed stimulus-responsiveness upon temperature, p H, light, or oxidizing/reducing agents. However, most of these studies mainly focus on the stimuli responsive sol-gel phase transition behavior, other physical properties changes behind the sol-gel transition phenomena(more than dual-responsiveness) have been rarely reported because this may require complicated chemical synthesis and rational molecular design. Electroactive supramolecular gels with multistimuli responsiveness were firstly fabricated through host-guest interactions based on an IL type asymmetric gemini guest. Owing to the multiple stimuli-responsiveness of the host-guest interactions, reversible sol-gel phase transition could be triggered by various stimuli, including temperature, electrochemical/chemical redox and anion-exchange reactions.Shape memory PIL gels with controllable macroscopic swelling degrees were firstly prepared via host-guest interaction. PILs with TFSI- anions were synthesized by the radical copolymerization and immersed in water and β-CD aqueous solutions, respectively. Quick swelling and shape memory behavior of the PIL gel were observed in β-CD aqueous solution.The main research work is as the follows:(1) Preparation of supramolecular gels with multistimuli responsiveness through host-guest interactions based on an IL type asymmetric gemini guest. Supramolecular gels based on the host-guest interactions between p AOI-β-CD(the host polymer) and IL type asymmetric gemini guest containing both Fc and TFSI– guest groups as a non-covalent cross-linker was firstly synthesized. This supramolecular gel exhibits multiple stimuli-responsive reversible sol-gel transitions upon temperature, electrochemical and chemical redox reactions, and anion-exchange. The results as follows: no additional supporting electrolytes are needed for the electrolysis of p AOI-β-CD/Fc-[BIM]TFSI complex system because Fc-[BIM]TFSI itself is intrinsically electroconductive, and reversible conductivity switching behavior was observed upon such stimuli at the same time.(2) Preparation of shape memory PIL gels controlled by host-guest interaction with β-CD. Shape memory PILs with TFSI– was firstly synthesized. The swelling behavior and shape-memory effect of the PIL gel in aqueous β-CD were investigated. The results as follows: The synthesized gels exhibit an excellent shape memory effect due to the hydrophobic-to-hydrophilic transition induced by β-CD, which extended the stimulus of swelling to be used to influence the supramolecular cross-linked gels.