Preparation And Properties Of Novel Ionogel Based On Hyperbranched Polymers

Ionogel electrolytes,as a new type of composite material based on ionic liquid,become a research focus in the fields of lithium batteries,supercapacitors,sensors and electrochemical brakes due to their excellent properties.However,the shortcomings of ionogel have gradually emerged.For example,the high mechanical properties of the ionogel is not compatible with high electrical conductivity,the poor thermomechanical,tensile properties and the weak stimuli-responsability.Therefore,how to solve the disadvantages of ionogel in practical applications has become more and more the focus of current research.In the present work,some chemically cross-linked ionogels with high performance were successfully synthesized by photopolymerization or thermal polymerization with hyperbranched polymers in ionic liquid,and their microstructure,mechanical property,thermal stability,ionic conductivities,and stimuli-responsive behavior of the ionogels were investigated systematically.The main results of this dissertation are as follows:(1)A new type of chemically cross-linked ionogels was successfully synthesized by photopolymerization of hyperbranched aliphatic polyester with terminal acryloyl functional groups in an ionic liquid.The room temperature ionic conductivity of all the ionogels exceeded 10~-33 S/cm and has reached the practical application level required for energy storage and conversion devices.Rheological measurements revealed that the plateaus modulus in storage modulus increase with increasing the content of hyperbranched aliphatic polyester(up to 10~5 Pa).The ionogels are very stable and the networks are not destroyed even at temperature up to 200 ~oC,as supported by the dynamic temperature sweep measurements.It was found to be thermally stable up to 371.3 ~oC.(2)Epoxy resin-based ionogels have been synthesized by two-steps method from amino-terminated polyoxypropylene(PEA)and glycidyl methacrylate(GMA)and ionic liquids as solvent and electrolyte.Rheological measurements revealed that the plateaus modulus in storage modulus increased with increasing the content of polymer monomer and crosslinking degree.The ionogels were very stable and the networks were not destroyed even at temperature up to 150 ~oC,as supported by the dynamic temperature sweep measurements.The room temperature ionic conductivity of all the ionogels increased with increasing the content of ionic liquids.Tensile properties test showed that the ionogels had an elongation at break of 123%.(3)Highly stretchable ionogels have been synthesized by two-steps method from hyperbranched poly(amido amine)s(HPAMAM)and glycidyl methacrylate(GMA)have been synthesized.Due to the unique structure of hyperbranched polyamidoamine(HPAMAM),the modulus of ionogel can reach 10~5 Pa,and the electrical conductivity and tensile properties are obviously improved.Tensile properties test shows that the ionogel has an elongation at break of 486%.Ionogel has obvious fluorescence at room temperature.It is worth noting that the ionogel can be easily repaired at higher temperature by a special reaction between the amino group and the epoxy.(4)Thermosensitive ionogels from N-Isopropylacrylamide(NIPAM)and glycidyl methacrylate(GMA)have been synthesized by stepwise photopolymerization.The ionogel gradually becomes transparent as the temperature increases.Rheological measurements revealed that the plateaus modulus in storage modulus of up to 10~5 Pa.The modulus of the ionogel gradually decreases with the increase of temperature,but the ionogel shape can be maintained all the time,and the ionogel gradually recovers when the temperature is lowered.It is worth noted that the ionogel has strong fluorescence,and the fluorescence intensity gradually decreased with the temperature increased,and the fluorescence still appears after returning to room temperature.