Multifunctional actuation systems responding to chemical gradients

The ability to manipulate the movement of surface microstructures is essential for the development of dynamic, responsive materials. We demonstrate that in addition to bulk actuation upon drying, a unique type of highly localized, directional actuation can be achieved when microstructures embedded in pH responsive gel are exposed to pH gradients. Theory and modelling elucidates the underlying mechanism behind this novel approach to inducing responsive actuation.