Preparation And Properties Of PAMAM Dendrimer Based Ionogel

The new types of polymer lithium-ion battery and flexible supercapacitor have attracted much attention as a hot research area throughout the world,which the traditional gel polymer electrolyte are replaced by ionogels.However,the current polymer matrix is limited to crystalline linear polymer homopolymer/copolymer,ion migration is difficult,the functional groups are seldom,and it is difficult to adsorb more ionic liquid,ion conductivity and mechanical strength can not meet the requirements in process of assembly and use.Meanwhile,the current gel polymer electrolyte prone to cracks and other structural defects in the process of manufacture or repeated use,and the service life is very short.Therefore,how to achieve the ionogel with good mechanical properties and high ionic conductivity at the same time,and how to repair the damage in manufacture or use is the key issues in the current research of ionogel electrolyte materials.In the present work,a new type of high performance ionogel with special network skeleton and ion transport channel was prepared by in situ crosslinking of polyamide amine?PMAAM?dendrimer with amorphous structure and rich functional groups.The self-repairing mechanism,electrical performance,and mechanical properties were researched in detail.The microcosmic mechanism and mechanical response mechanism of high ionic conductivity of ionogel were investigated.The phase behavior of PAMAM/ionic liquid binary system was also studied.The main results of this dissertation are as follows:?1?Self-healing ionogels with covalent polymeric networks based on dendritic poly?amido amine?s?PAMAM?have been synthesized by in situ amines crosslinking via the Schiff base reaction,and ionic liquids as solvent and electrolyte.Rheological measurements revealed that the plateaus modulus in storage modulus increase with increasing the content of dendrimers,and with increasing generation of dendrimers results in the decrease of the plateaus modulus due to geometrical reasons.The ionogels are very stable and the reversible covalent networks are not destroyed even at temperature up to 160 oC,as supported by the dynamic temperature sweep measurements.The ionogels exhibit high ionic conductivity and room temperature ionic conductivity can reach 10-2 S/cm.Remarkably,the ionogels is degradable in a large amount of water and the PAMAM and ionic liquid are recyclable.?2?Ionogels with imidazolium cycle cross-links based on polyamidoamine?PAMAM?dendrimers have been achieved via one-pot modified Debus-Radziszewski reaction,and ionic liquids as solvent and electrolyte.Ionic conductivity up to 6.8 mS/cm was achieved in samples with an adjustable elastic modulus?104-106 Pa?at room temperature.Crucially,these ionogels are robust gels even at temperature up to 160 oC,as supported by the dynamic temperature sweep measurements.The ionogel was tested as flexible gel electrolyte for supercapacitor device,and expressed good cycling performance,the measured specific capacitance was maintained for up to 5000 charge-discharge cycles.?3?Phase behaviors of the PAMAM/[BMIM][BF₄] binary system were studied by uv-visible spectrophotometer and optical microscope.The results show that the half generation system is compatible,while the whole generation systems show phase separation.The whole generation of PAMAM/[BMIM][BF₄] system presents the UCST behavior,and the upper critical temperature increases with increasing the generation of PAMAM.For the PAMAM G1.0,PAMAM G3.0 and PAMAM G5.0 systems,the critical temperature Tc is 92,124 and 130 °C,respectively,and the critical composition?Wc?is 10%.