Synthesis Of Oligomeric Poly (Ionic Liquid) And Its Physicochemical Properties

Poly(ionic liquid)s are generally a type of ionic polymer obtained by polymerization of ionic liquid monomers,or grafting ionic liquid units onto the polymer backbone,which is a manifestation of the designability of ionic liquids.Poly(ionic liquid)s have a polymer backbone and ionic liquid structural units,and share the advantages of ionic liquids and polymers,such as lower vapor pressure,good thermal stability,wide electrochemical window,non-volatile,and adjustable ionic conductivity,controllable structure and molecular weight,controllable hydrophilicity/hydrophobicity,etc.Therefore,poly(ionic liquid)s have the prominent applications in many scientific fields including electrochemistry,catalysis,smart materials,new energy materials,flexible electronic devices,controlled drug release,gas separation,etc.Poly(ionic liquid)not only inherits the designability advantages of ionic liquids,it can also control its physical and chemical properties by controlling the degree of polymerization or copolymerization with other monomers,and it has superior structural designability than ionic liquids.How to make best use of the advantages of designability to build poly(ionic liquid)s multi-level micro-nano structure with more optimized structure and performance has important reference for new material design.In this paper,a class of PEG-based functional ionic liquids and imidazole poly(ionic liquid)s were designed and synthesized,and the basic physical and chemical properties of these functional poly(ionic liquid)s were studied.The main research contents of this paper are as follows:1.A series of PEG functional ionic liquids were synthesized including PEG_m(mim)X(m=350,550,750,1000),PEG_m(bim)X(m=350,550,750,1000),PEG_m(mim)₂(X)₂(m=600,1000),PEG_m(bim)₂(X)₂(m=600,1000),where X is Cl^-,Tf₂N^-and AOT,etc.The structure of these ionic liquids were characterized by NMR and IR.In addition,DSC and TGA were used to determine the physical and chemical properties of these ionic liquids,such as the glass transition temperature and thermal decomposition temperature.2.The basic physical and chemical properties of PEG functional ionic liquid such as density,viscosity and lower critical solution temperature behavior in water are studied.The aggregation properties of PEG-based functional ionic liquid surfactants in water are discussed.The critical micelle concentration(cmc)of surfactants in water was measured by conductivity,surface tension,etc.Finally,the size and distribution characteristics of aggregates were determined by the dynamic light scattering and cryo-electron microscopy.3.A series of poly(ionic liquid)s based on the copolymerization of 1-alkyl-3-vinylimidazole bromide and 1-methoxyethyl-3-vinylimidazole bromide were synthesized.The poly(ionic liquid)s were characterized by NMR,IR,etc.The thermal decomposition temperature of these poly(ionic liquid)s has been measured by TGA.Moreover,the cmc of these poly(ionic liquid)s in water was measured by conductivity,and the particle size and distribution of the aggregates were characterized by dynamic light scattering,small angle x-ray scattering etc.