Preparation And Performance Of Electric Field Responsive Polymer Hydrogels

Conductive fillers or conductive polymers combine with cross-linked hydrogels to form conductive hydrogels,or conductive composite material,which have potential applications in capacitors,sensors,artificial muscles,etc.Because the hole convection of macro-pore hydrogels interconnected hole network is faster than slow diffusion process of non-porous hydrogels by polymer network,the absorbing or releasing solvents of large-hole hydrogels,aperture greater than 50 nm,is faster than that of nonporous hydrogels.Electro-responsive hydrogels with both conductive properties and hole structures has still seldom been reported.In consideration of the characteristics of Nickel-Foam(NF)with high surface area,good conductivity and three-dimensional connecting macro-pore texture,and its missing application in the field of hydrogels.Therefore,the writer would like to take it as an idea to prepare a series of novel porous electrically-conductive electro-responsive hydrogels.Meanwhile,hydrogels mother liquor was injected into the connecting pores of porous electrically-conductive electroresponsive hydrogels to form electrically-conductive electro-responsive hydrogels with a carbon-nanotubes-enriched(CNTs-enriched)three-dimensional conductive network and a physical-phase-type three dimensional interpenetrating network.In this dissertation,attapulgite(ATP)and pyrrole were firstly polymerized by chemical oxidation to form a core-shell structure conductive composite and it combine with polymer hydrogels to obtain electro-responsive hydrogels of nanofibrous attapulgite coated by polypyrrole.Subsequently,the facile NF is taken as the skeleton of the hydrogels and the polymer hydrogels mother liquor is pumped into the inside holes of NF by means of vacuum pumping.To obtain NF-profiled connecting pores electro-responsive hydrogels,the NF skeleton was etched completely by hydrochloric acid.It is considered as template for interfacial polymerization polyaniline to form high-quality and fast response rate porous hydrogels.Furthermore,novel method for preparing CNTs-enriched conductive hydrogels,CNTs depositing to NF,hydrogels-A filling into body-phase hole of CNTs-attached-NF,etching the NF skeleton and hydrogels-B filling into leaving NF-profiled three-dimensional connecting pores,is proposed.The novel design about two-physical-phase-type interpenetrating network and three-dimensional CNTs-enriched conductive network of the electric-field stimulation hydrogels will lead to outstanding electric-conductive performance and fast electrical response behavior of the electric-field response hydrogels.Specifically,the detailed research results are as follows:Firstly,Iron trichloride hexahydrate as oxidant,Dodecyl sulfonic acid sodium salt as doping agent,ATP/PPy composite particle was prepared by surface-initiated in situ polymerization.The pyrrole monomer on the surface of the attapulgite was completed polymerization and the ATP@PPy conductive composite fillers of core-shell structure was obtained.It was taken advantage of preparing P(AMPS-co-AA)/CNTs/ATP@PPy hydrogels with high mechanical strength and rapid electric-field response by means of thermal-initiated free radical polymerization.Secondly,in response to the slow response speed of hydrogels,NF was used as innovatively hard template to form NF-profiled connecting pores in the hydrogels body.The NF was placed in comonomers dispersion of acrylic acid and 2-acrylamido-2-methyl-1-propanesulfonic acid.The thermal-initiated free radical copolymerization was completed and large porous P(AMPS-co-AA)/CNTs hydrogels with NF-profiled connecting pores was obtained after etched NF skeleton.Subsequently,the interfacial polymerization was completed to form the porous P(AMPS-co-AA)/CNTs/polyaniline conductive composite hydrogels with fast electrical response behavior.Finally,in terms of current issues of poor conductivity and mechanical properties of hydrogels,we proposed novel preparation method of P(AMPS-co-AA)/CNTs//CNTs NF-profiled two-phase-type interpenetrating electric-field response hydrogels with CNT-enriched NF-profiled three-dimensional conductive network.The CNTs-attached NF was immersed into the comonomers dispersion A,which was pumped into the inside holes of the CNTs-attached NF by means of vacuum pumping and thermalinitiated polymerization was performed.The NF skeleton was etched by hydrochloric acid to obtain porous P(AMPS-co-AA)/CNTs//CNTs hydrogels with a NF-profiled three-dimensional connecting pores and a CNTs-enriched NF-profiled three-dimensional conductive network.Subsequently,the comonomers dispersion B was pumped into the NF-profiled connecting pores left behind etching NF by means of vacuum pumping and thermal-initiated free radical polymerization was performed to obtain P(AMPS-coAA)/CNTs//CNTs NF-profiled two-phase-type interpenetrating hydrogels with CNTsenriched NF-profiled three-dimensional conductive network.Our innovative twophase-type interpenetrating co-network may provide a significant variable strategy to fabricate high-performance smart hydrogels.