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Preparation Of Polyampholyte Hydrogel And Its Application In Fexible Sensing

Posted on:2022-08-12Degree:MasterType:Thesis
Country:ChinaCandidate:X Y LiFull Text:PDF
GTID:2518306482494494Subject:Polymer Chemistry and Physics
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Hydrogel was a kind of soft material as a three-dimensional network structure polymer with high water content.Due to its excellent flexibility,this material had been widely studied and paid attention to by scientific researchers.However,the application of traditional hydrogel materials was often subject to various defects and problems of its own,resulting in limited applications.For example,in a cold area's temperature environment,the hydrogel lost its flexibility and stretchability,or multiple reciprocating stretching activities destroyed the hydrogel network structure.These resulted significantly affect the practical application of hydrogels.Therefore,it was a significant study to realize that the hydrogel had self-healing properties and excellent anti-freezing in cold environments.Here,we successfully introduced the zwitterionic monomers sodium methacrylate and[2-(methacryloyloxy)ethyl] trimethyl ammonium chloride(DMC)into the hydrophobically associated polyacrylamide hydrogel system.This MAANa/DMC polyampholyte hydrogel,which was copolymerized by zwitterionic monomer and acrylamide,had been successfully prepared.Through physical interaction and the hydrophobic system's network structure,a hydrogel with a hybrid structure network was formed.This physical interaction was an electrostatic interaction caused by the positive and negative groups attracting each other after the polymer branched chain groups in the polyampholyte hydrogel ionize freely moving ions.Due to the existence of electrostatic interaction,the self-recovery property of the hydrogel was greatly improved.At the same time,the free ions ionized by the polymer branched chain were dispersed in the hydrogel system,which reduced the freezing point of the polyampholyte hydrogel and improved the conductivity of the hydrogel.Its antifreeze temperature could reach-31.7 ? measured by differential scanning calorimetry(DSC).The conductivity of the polyampholyte hydrogel at room temperature was maintained at a maximum of 0.057 S/cm,and the conductivity at low temperature could still reach 0.035S/cm.The good mechanical properties made the fracture stress of the polyampholyte hydrogel reach 370 k Pa and the elongation at break was 1758%.MAANa/DMC polyampholyte hydrogel had excellent fatigue resistance,self-recovery properties,anti-freezing and low temperature conductivity,which broadened the application environment of hydrogel as a flexible wearable strain sensor and solved the predicament of strain sensor inactivation when used in cold areas and winter.The excellent properties of polyampholyte hydrogel provided us with new ideas for designing a strain sensor for human motion signals and biological physiological signal monitoring.It is foreseeable that MAANa/DMC polyampholyte hydrogels will provide stable performance in complex temperature environments and have broad application prospects in physiological signal monitoring,electronic skin and wearable devices.
Keywords/Search Tags:Polyelectrolyte hydrogel, Anti-freezing, Low temperature conductivity, Low temperature strain sensing
PDF Full Text Request
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