Investigation Of Photocuring PVA-SBQ/PVA Hydrogel And Application In 3D Printing And Flexible Sensor

Hydrogels are flexible materials with high water content whose threedimensional network structure is similar with the extracellular matrix.The physical and chemical properties of hydrogels are easily tuned,especially the modulus can be adjusted to be consistent with human skin tissue.Therefore,they are widely used in biological tissue engineering,flexible devices and wearable devices.PVA hydrogels have been extensively studied,however,the main drive for PVA materials to become hydrogels are hydrogen bond or crystallization and the shape of hydrogels depends on template which lacks customization.In this work,styrylpyridine(SBQ)functionalized PVA made PVA processing photocurable properties because SBQ could undergo photodimerization.The photocurable 3D printability of PVA-based hydrogels without photo-initiator was achieved and hydrogel devices with stable sensing was also prepared.The main researches were as follows:1.Non-ionized polyvinyl alcohol-styrylpyridine(PVA-SBQ)was compounded with PVA following different ratios to prepare hydrogels which were studied with different mechanical properties through adjusting preparation process.The ratio 1:1 of PVA-SBQ with PVA mixture were prepared for photocurable 3D printing precursor solution.Meanwhile,high-precision 3D printing was achieved by adjusting printing parameters.Different from radical photopolymerization,this hydrogel utilized the photodimerization of SBQ where the photo-initiator was not included.After printing,there were not initiators and their residues in the production.In addition,it had widelyapplication prospect in the field of biological tissue engineering with low cytotoxicity and high biocompatibility which was indicated by vitro cell experiments.2.The mixture solution of ionized PVA-SBQ and PVA was applied to prepare the hydrogel through in-situ photocuring,which was also used to prepared strain sensor.The linear response of the hydrogel resistance with strain was achieved with the GF of 1.2.The prepared devices also had stable sensing performance(under 200 stable cycles)and wide detection range(from 1%,2%,5%,10%little tensile strains to 30%,50%,100%big tensile strains).Furthermore,we also studied the sensor device based on the hydrogel about the monitoring of human body movements,human pulse and finger bending which was monitored stably.3.In this work,flexible sensors which withstood low temperature was prepared through introducing glycerol into the system of ionized PVA-SBQ and PVA.It can be used normally within the temperature range of-30℃-30℃,and the flexible sensors always had the stable sensing performance.Furthermore,the movement of the human body about the bending of the fingers was also successfully monitored even the temperature dropped to-30℃.