The Morphological Control Of Cross-linked Poly Imidazolyl Ionic Liquid Composites And Their Electrorheological Properties

Electrorheological（ER）fluid is a kind of intelligent response material,which can show a solid-liquid transformation with the change of external electric field,and thus has a good electric field response performance.Poly（ionic liquid）（PIL）is a kind of polyelectrolyte with broad prospects.There are free ions on its skeleton and therefore it can be used as dispersed phase and show good ER properties in ER fluid without water.The structure and properties of the poly（ionic liquid）can be adjusted by cross-linking,recombination and copolymerization.In this paper,polymerizable1-butyl-3-vinylimidazole tetrafluoroboric ionic liquid[C₄VIm][BF₄]was used as the basic research object and it was cross-linked polymerized,copolymerized respectively.And,Its cross-linked polymerized products were used to compound with other material.Finally,the target and the intermediate products were tested and analyzed by ¹H NMR,FT-IR,TGA,XRD,SEM and rotational rheometer.The main content is as follows:Firstly,homo-polymerized P[C₄VIm][BF₄]was synthesized by free radical dispersion polymerization using[C₄VIm][BF₄]as the monomer.Subsequently,the corresponding cross-linked poly（ionic liquid）（P[H/C₄VIm][BF₄]）was synthesized by using 1,6-hexamethyl-3,3?-bis-1-vinylimidazole tetrafluoborate（[HVIm][BF₄]）as the cross-linking agent and controlling its content at 10%and 20%.The results show that the poly（ionic liquid）with a cross-linking agent content of 20%has more regular spherical morphology and better ER properties.Secondly,P[H/C₄VIm][BF₄]@PANI core-shell composite particles were synthesized by low temperature interfacial polymerization with P[H/C₄VIm][BF₄]（20%）microsphere as the core and polyaniline（PANI）as the shell.Then the influence of PVP on the composite structure was explored.Finally,by adjusting the doping amount of aniline（Ani）,the influence of Ani on the morphology and ER properties of the composite particles was investigated.Various test and analysis results show that the addition of PVP makes the core-shell structure more uniform.It showed better morphology and best ER properties when the doping amount of Ani was 80%.Finally,the ionic liquid copolymer P[MMA/C₄VIm][BF₄]was synthesized by free radical copolymerization using ionic liquid[C₄VIm][BF₄]and methyl methacrylate（MMA）as comonomers.Then the copolymers P[E/MMA/C₄VIm][BF₄]and P[D/MMA/C₄VIm][BF₄]were synthesized by using EGDMA and DVB as cross-linking agents respectively.Various test and analysis results show that the addition of cross-linking agent can reduce the generation of self-polymerized particles and produce copolymerized particles with special morphologies.The ER results show that the copolymerized particles with DVB as cross-linking agent have better ER properties.