Preparation And Sensing Properties Of Environmentally Adaptable High-Toughness Conductive Polymer Organohydrogels

With the development of the times,flexible hydrogel strain sensors have broad application prospects in the fields of electronic skin,bioelectrodes,and flexible devices due to their excellent sensing performance and outstanding conformability.In this work,two kinds of conductive polymers were prepared by introducing dimethyl sulfoxide（DMSO）/water（H₂O）binary solvent and in situ polymerization.Conductive polymer organohydrogels with high toughness and environmental adaptability were tested for their mechanical properties,environmental adaptability and sensing properties,and explored their use as flexible wearable strain sensors and flexible bioelectrodes in monitoring human physiological signals and other applications.First,polyvinyl alcohol（PVA）as the hydrogel network,DMSO/H₂O binary solvent as the antifreeze solvent,and pyrrole（Py）as the functional polymerizable conductive monomer,multiple non-covalent crosslinks were induced by freeze-thaw cycles.Py was oxidized to form polypyrrole（PPy）while soaking in a mixed solution of iron sulfate（Fe₂（SO₄）₃）.PVA/PPy organohydrogels with high toughness and resistance to extreme temperatures were successfully synthesized and used to construct flexible strain sensors.Due to the formation of multiple crosslinks,the organohydrogels has excellent mechanical strength,with a toughness as high as 22.64 MJ/m³,a tensile strength of 7.8 MPa.The introduction of strong hydrogen bonding enables the organohydrogels to still work normally at a temperature of-45 to 65°C,and the conductivity remains at 0.14 S/m when the temperature drops to-45°C.The fabricated organohydrogels sensor exhibits high sensitivity（GF=5.1）,low response time（<0.3 s）,and wide strain range（0-500%）,and exhibits stable performance even at extreme temperatures.Secondly,DMSO/H₂O as binary solvent,acrylic acid（AA）and 2-methoxyethyl acrylate（MEA）were used as hydrogel monomers,and aniline（ANI）was used as a functional polymerizable conductive monomer.Immersed in a mixed solution of ammonium persulfate（APS）/phytic acid（PA）,thereby inducing hydrophobic groups to aggregate with each other to form hydrophobic interactions and ANI to be oxidized to form polyaniline（PANI）,successfully preparing a polyaniline（PANI）with high toughness and environmental adaptability P（AA-co-MEA）/PANI organohydrogels.Organohydrogels had high toughness（413.2 k J/m³）and good tensile strain（600%）.The organohydrogels had negative swelling ratios in various solvents,and after drying at room temperature for15 days,they still maintained excellent mechanical properties（320 k Pa,810%）and electrical conductivity（0.68 m S/cm）.Even at a temperature of-45°C,the strain at break was as high as 1000%,and the electrical conductivity reached 0.61 m S/cm,showed excellent environmental adaptability.The sensitivity（GF）of the organohydrogels was as high as 5.49,it can repeated 500 cycles strain sensing tests and it still exhibited good sensing performance even after being soaked in water for 15 days.These two works provide new ideas for broadening the potential applications of flexible strain sensors with high toughness in extreme environments.