Preparation Of Poly(Ionic Liquid) Nanoaggregates Through RAFT Polymerization-induced Self-assembly

As adopted from the excellent properties of both ionic liquid and polymers,poly?ionic liquid??PIL?nanoaggregates have been prominent in a variety of applications,such as catalysis,separation and energy.The current method for PIL nanoaggregates preparation though PIL diblock copolymer self-assembly in solvents that are selective for only one block,which suffers from a series of problems,such as cumbersome preparation steps,very difficult to realize structural regulation on particle morphology and aggregation state.How to prepare PIL nanoaggregates of well-defined morphologies in an efficient way has become a challenge in PIL research.Herein,we proposed the preparation of PIL nanoaggregates through polymerization induced self-assembly?PISA?,which usually uses dispersion polymerization,simple synthesis steps,and well-defined morphologies.The main research contents are as follows:1.Eight different kinds of ionic liquid monomers?vinylimidazole-type,acrylate imidazole-type and methacrylate imidazole-type?have been synthesized,which were further polymerized into PIL via solution free radical polymerization.By comparing the solubility of IL monomers and PILs in water,methanol and ethanol,we found that3-n-dodecyl-1-vinylimidazolium bromide(C₁₂VIm-Br)and 3-benzyl-1-vinylimi-dazolium bromide?BVIB?were suitable for aqueous dispersion polymerization systems.2.PIL nanoaggregates have been successfully prepared through the RAFT/MADIX aqueous PISA of C₁₂VIm-Br,using PEG-xanthate as the macro-CTA.The morphological transitions from rods-to-branched rods-to-highly branched networks were observed with DP increase from 5 to 200 at 5 wt%solid content.With an increase in solids content from 5 to 15 wt%,short rods grew into longer ones and aggregation occurred.These PIL nanoaggregates were highly responsive to the salt concentration.3.PEG₄₅-b-PBVIB₁₁₆ spherical nanoaggregates with an average particle size of180 nm have been prepared through RAFT-PISA,by using PEG-xanthate as macro-CTA,as initiated by photoinitiator HMPP.4.V-50 was used as initiator,PEG-trithiocarbonate was used as macro-CTA,a novel coordination-driven PISA system has been successfully constructed by introducing the coordination interaction between Zn²⁺and vinyl imidazole?VIM?as the driving force.When the solid content was 10 wt%and the mole ratio of Zn²⁺/VIM was fixed at 2,network-like morphology of PIL nanoaggregates was observed.To the best of our knowledge,this is the first report on the realization of PISA via coordination as the driving force,which would provide some new thoughts for the preparation of polymeric nanoaggregation.