Electrostimulated reversible swelling/shrinking behavior of electroactive p(AA-BAC)/Cu(II) microgel monolayer on Au electrode surface

Electroactive, electrosensitive and fast reacting p(AA-BAC)/Cu(II) microlayers were successfully constructed on the Au electrode surface. The layers consisted of microgel particles composed of poly(acrylic acid) cross-linked with N,N-bis(acryloyl)cystamine (BAC). The p(AA-BAC) microgels were synthesized using distillation precipitation polymerization. The deposition of microgels was due to chemisorption of -S-S- groups from BAC on the gold surface. After the deposition, copper(II) ions were added and bound with the polymer network through the coordination bonds with the carboxylic groups. This addition increased the number of crosslinking points in the gel. The microgel particles were characterized using SEM, QCM-D, dynamic light scattering and electrochemistry. Thanks to reversibility of the electroreduction and electrooxidation of the copper ions (from Cu(II) to Cu(I) and from Cu(I) to Cu(II)) the obtained layers of p(AA-BAC)/Cu(II) microparticles on gold could undergo multiple fast swelling and shrinking processes triggered by application of appropriate sequence of potentials.