Compliance-mediated topographic oscillation of polarized light triggered liquid crystal coating

The ability to induce oscillating surface topographies in light-responsive liquid crystal networks on-demand by light is interesting for applications in soft robotics, self-cleaning surfaces, and haptics. However, the common height of these surface features is in the range of tens of nanometer, which limits their applications. Here a photoresponsive liquid crystal network coating with a patterned director motive exhibiting surface features that oscillate dynamically when addressed by light with modulated polarization is reported. By utilizing a compliant intermediate layer, the surface topographies increase with a factor 10, from roughly 70–100 nm to 1 µm. This increase in topography height is accompanied by a superimposed dynamic oscillation with an amplitude of ≈100 nm. These values can be translated to a 16.7% average static strain with 3.3% oscillations with respect to the coating thickness. Moreover, utilizing the complying support increases the maximum rotation speeds with an in-phase response from 2.5 up to 25° s−1. However, at this maximized rotation speed the oscillation amplitude decreases to about half of the initial value.