Controllable reconfiguration of bio-inspired nanoparticle networks under torsion
Abstract
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 (gLSM) is based on a finite element approach and thus, 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. In particular, 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 can form a corrugated structure when the temperature is decreased. Hence, the material can be dynamically and reversibly switched between a planar and corrugated geometry with variations in temperature. We use the same approach to design gels that encompass both positive and negative curvatures around a saddle point. In this manner, we are attempting to design gels with 3D printed architectures that undergo structural reconfiguration and enable new functionality.
