Frictional Property of Hydrogels Prepared under Electric Fields

We studied frictional property of hydrogels prepared under electric fields. Pre-gel solution was filled between two electrodes and voltage was applied during crosslinking reactions. After removing the gel from the electrodes, frictional testing for the gel surfaces prepared on both cathode and anode was performed against a silicon dioxide coated surface. For the gels containing two types of monomers, an electrolyte and a neutral, friction coefficient for the gel surface prepared on the anode was much smaller than that for the cathode as well as that without electric voltage. In contrast, no significant difference was seen between the two surfaces for the single-component gels. Our results suggest that this simple technique of applying electric voltage during gelation is effective for controlling and reducing friction of hydrogels.