(122c) Stimuli Responsive Reversible Adhesion between Physical and Chemical Networks

This work will present studies from our lab on the electrically induced adhesion of hydrogels and beads made from polyelectrolytes. The basic phenomenon involves crosslinked acrylate hydrogels made with either anionic co-monomers (such as sodium acrylate) or cationic co-monomers (such as aminated acrylates). When a rectangular strip of a cationic gel (connected to an anode) is contacted for just a few seconds with a strip of anionic gel (connected to a cathode) under a voltage of ~ 10 V, the two gel strips form a strong adhesive bond. When the polarity of the electrodes is reversed, the phenomenon is reversed, i.e., the gels can be easily detached.

While the above phenomenon of ‘electro-adhesion’ has been reported before for hydrogels, we show that it is much more general and widespread. Specifically, we can substitute either of the above gels with a spherical bead made using charged biopolymers such as chitosan or alginate. The same electro-adhesion works to join beads to gels, or two beads to each other. In turn, electro-adhesion can be applied for the pick-up and drop-off of soft cargo, and for the sorting of beads.