{
    "protocol": "Prepare an ethanol/water solvent system to regulate hydrogen bond cross-linking between polyvinyl alcohol (PVA) and tannic acid (TA). Create a 'hydrogel paint' using a one-pot method. Apply the hydrogel paint onto the surface of stainless-steel mesh (SSM) using a common paint application method. Allow the ethanol in the hydrogel paint to evaporate gradually, enabling the reestablishment of hydrogen bond cross-linking between PVA and TA, resulting in a stable hydrogel coating layer.Dissolve poly(vinyl alcohol) (PVA) and the crosslinking agent, tannic acid (TA), in a solvent system consisting of ethanol and water. The final optimized volume ratio of water to ethanol should be 5:5 to ensure uniform fluidity and good processability. Mix the components until a stable and homogeneous hydrogel paint is obtained. Apply the hydrogel paint to the surface of the porous substrate (SSM) using one of the following methods: dipping, spraying, brushing, or shearing. Remove the ethanol from the coating by volatilization to re-establish the hydrogen bond between PVA and TA, forming a 3D network structure. Optionally, integrate an appropriate amount of nano-sized SiO2 to enhance the surface roughness and stability of the PVA-TA gel.PVA (3.0 g) and TA (3.0 g) were dissolved in 94.0 g mixed solvent (deionized water/ethanol = 1:1 v/v) with stirring at approximately 90°C for 6 hours to obtain PVA-TA hydrogel paint. For PVA-TA@SiO2 hydrogel paint, 0.6 g SiO2 was added to the water/ethanol solvent under ultra-sonication for 30 minutes before adding PVA and TA. The SSM (average pore diameter of approximately 50 μm) was immersed in the pre-gel solution for 2 minutes, then taken out and dried at room temperature to obtain the hydrogel-coated mesh."
}