Controllable Dynamic Reconfiguration in Fiber-decorated Thermo-responsive Gels

Using computational modeling, we simulate gels where elastic fibers are localized on the surface of the polymer network. Our computational approach, the gel lattice spring model, allows us to numerically solve the elastodynamic equations that characterize the behavior of thermo-responsive polymer gels. Via this model, we determine how to arrange the fibers on the outer layer(s) of the gel to achieve new shape changes that could not be achieved with the fibers localized in the bulk of the material. We focus on gels with a lower critical solubility temperature (LCST) and show that the fibers inhibit the swelling of the gel as the temperature is lowered and inhibit the shrinking of the gel as the temperature is increased. This behavior can lead to novel 3D shape changes, such as gels that encompass negative Gaussian curvature around a saddle point. We show that if an arrangement of fibers is placed on the top of an initially planar gel and the same arrangement is placed in an adjacent region at the bottom of the gel, the system be dynamically and reversibly switched between a planar and corrugated geometry with variations in temperature. In this manner, we are attempting to design gels with 3D architectures that undergo structural reconfiguration and enable new functionality.