BENDING BEHAVIOR OF POLY (VINYL ALCOHOL) POLY (ACRYLIC-ACID) HYDROGELROD INCLUDING ELECTRODES AND ITS APPLICATION

Square-rod shaped poly (vinyl alcohol) hydrogel containing poly (acryl ic acid) with two platinum wire electrodes in its body was prepared an d its characteristics were examined. Upon application of direct curren t to the electrodes in NaOH aqueous solution, the gel bent due to shri nkage of the gel around the anode. At this time, the bending rate and deflection were dependent on both the applied Voltage and the concentr ation of NaOHaq. Reversing the polarity, the hydrogel which had bent s howed stretching. The gel was able to repeat the cycle of bending and stretching as the polarity was alternated. This hydrogel with electrod es has a simpler structure than does the bimetal system, Strong and fl exible hydrogels can be obtained by a simple process of freezing-thawi ng a mixture of two kinds of poly-aqueous solutions, without any chemi cal reaction. Therefore, bending and stretching behavior is considered to be of wide application and was applied to a gripper system. It had the ability to continue gripping material in air as well as in NaOHaq .