Modeling directed motion of polymer gels

We utilize the 3D computational gel lattice spring approach to model the directed motion of polymer gels. We consider a lower critical solution temperature (LCST) gel, which is placed between two parallel plates. Upon a decrease in temperature, the plates constrain the swelling of the gel to the direction parallel to the surface. We assume that in the course of swelling, the gel slides along the confining surfaces with a local friction coefficient that is proportional to the normal stress (Newtonian friction). Using the gel lattice spring model, we demonstrate that the gel can attain directed motion with the application of an externally controlled temperature stimulus. In a system containing several gel pieces, the gels self-organize to exhibit concerted movement. The reported results can be used to design advanced gel-based actuators.