Synthesis of polyacrylamide hydrogels as p-n-junction with ionic charge carriers

Three different designs for p-n junctions were formed with p-and n-type polyacrylamide hydrogels (PAAm) doped with positive (Na⁺) and negative (Br^-) ions as charge carriers. First, previously synthesized p-and n-type gels in slab forms were contacted physically with together. Second, having synthesized p-type gel, n-type pregel solution was poured onto p-type slab gel for synthesis. Thus, p-and n-type gels were synthesized as to be contacted chemically together. Third, first p-type and n-type pregel solutions were mixed together, then the mixing was poured into a pot to form a layer, and then the reaction was performed under an electric field for directing the dopants on the opposite sides. The rectification efficiencies of all these junctions were discussed in detail. POLYM. ENG. SCI., 54:2799-2805, 2014.