Study On Stimuli-responsive Materials Based On Poly (Ionic Liquid)

Stimuli-responsive polymers are materials that can respond to external stimuli,such as temperature,light,pH,electric field and magnetic fields and its physical-chemical property will be changed that have potential applications in smart materials,biomedical sciences and matrix chemistry.Ionic liquids(ILs)are organic salts are composed of anion and cation with low volatility,high thermal stability,chemical stability and wide electrochemical windows.Polymeric ionic liquids(PILs,polymers formed from IL monomers)combine the novel properties of both ILs and the mechanical durability and dimensional control of polymers.Numerous studies have been devoted to temperature,pH and electro-responsive copolymers since they exhibit abrupt and obvious changes under environmental conditions.However,it is relatively time-consuming and tedious for the synthesis and purification of well-defined block copolymers which may retard their practical applications.Therefore,random copolymers can be easily prepared in a single polymerization step and are convenient in the preparation of “smart” or “intelligent” materials.The main research work is summed as the follows:(1)Preparation of thermo-and pH-responvive poly(ionic liquid)membranes.Imidazolium ionic liquid monomer with different anions were firstly synthesized.The PIL membranes were prepared by the copolymerization of IL monomer acrylic acid,N-isopropylacrylamide,acrylonitrile and divinylbenzene by irradiation with UV light of 250 nm wavelength.By temperature,pH(solvent/gas)stimulus of the reversible change implemented that the optical properties and macroscopic change in shape of PIL membranes were investigated.The results as follows: the transmittance and macroscopic change in shape of the prepared PIL membranes were mainly determined by the hydrophobicity of counter anions,temperature,concentration of AA units and pH.(2)Preparation of thermo-and electro-dual responsive poly(ionic liquid)(PIL)electrolyte based smart windows.Diallyl viologen(DAV)and diacryloyl viologen(DACV)were firstly synthesized and applied as both the cross-linking agents and EC materials.PIL based electrolyte gels were synthesized by co-polymerization of N-isopropylacrylamide(NIPAM)with(or without)3-butyl-1-vinyl-imidazolium bromide([BVIm][Br]).Then,the electrolyte gels were sandwiched with a second ITO glass,and firmly sealed by 100 μm thick double-sided.The tunable optical properties of the thermo-and electro-devices(TEDs)in response to both thermo-and electro-stimuli behaviors were studied.The results as follows: The prepared TEDs exhibit tunable transparency and electrochromic properties due to the thermo-sensitive property of poly(N-isopropylacrylamide)(PNIPAM)and the electrochromic property of viologen moieties,respectively.