Synthesis Of Polyvinyl Alcohol Gel Materials And Its Application In Wound Dressings And Flexible Wearable Sensors

Polyvinyl alcohol(PVA)is a kind of polymer with good biocompatibility.It has remarkable water solubility due to the abundant hydroxyl groups,which can be utilized to form many functional materials through non-covalent or covalent bond.Recently,numerous gel-like materials based on PVA has been developed that have broad application prospect in many fields.This thesis introduces the synthesis protocols for PVA hydrogel or organogel with low-cost precursors via a very straightforward route,which were employed as epidermal wound dressings for rats and wearable strain sensors for monitoring human movement.The detailed content includes two parts as follows:(1)A flexible hydrogel was fabricated,using PVA as the backbone that can interact with phytic acid(PA)and tannic acid(TA).The final product could be produced in a short time(within 10 s)through the hydrogen bonding formed among PVA,PA and TA that can readily occur upon their mixing.The as-prepared hydrogel has high stretchability(～500%)and superfast self-healing ability(fracture healed with 10 s).The dissociation of phenolic hydroxyls in TA and phosphate groups in PA endows the hydrogel with conductivity,which would produce electrical signal change under physical deformation,hence,it works as a strain sensor when responding to human movement.Benefitting from the super-fast self-healing ability,a tensile sensor possessing rapid self-restoration was established with the assistance of a latex rubber hose(LRH).The hydrogel was also used as epidermal wound dressings for rats in view of the inhibition effect towards gram-positive/negative bacteria,Staphylococcus Aureus(S.Aureus)and Esherichia coli(E.coli),as the representatives,as well as eukaryotic yeast.The hydrogel product has the function of resisting wound infection,meanwhile promoting tissue proliferation and wound healing.(2)In this thesis,an organogel(PVA/PPy)was obtained using dimethyl sulfoxide(DMSO)as solvent,and PVA as the backbone,in which TA and pyrrole(Py)molecules were also added to form hydrogen bonding with PVA chain and function as the conductive additive upon its polymerization(PPy)induced by PA and ammonium persulfate(APS),respectively.The introduction of organic solvent improved the mechanical property and the environmental stability of the PVA/PPy organogel by the anti-dehydration effect(stable sensing performance can be maintained for more than 48 hours).This work exhibits impressive performance of the PVA/PPy organogel in accurate monitoring of human movements and subtle physiological signals(e.g.movement on pulse,throat,etc.).