Abstract
Liquid crystal surfaces can undergo topographical morphing in response to external cues. These shape-shifting coatings promise a revolution in various applications, from haptic feedback in soft robotics or displays to self-cleaning solar panels. The changes in surface topography can be controlled by tailoring the molecular architecture and mechanics of the liquid crystal network. However, the nanoscopic mechanisms that drive morphological transitions remain unclear. Here, we introduce a frequency-resolved nanostrain imaging method to elucidate the emergent dynamics underlying field-induced shape-shifting. We show how surface morphing occurs in three distinct stages: (i) the molecular dipoles oscillate with the alternating field (10–100 ms), (ii) this leads to collective plasticization of the glassy network (~1 s), (iii) culminating in actuation of the topography (10–100 s). The first stage appears universal and governed by dielectric coupling. By contrast, yielding and deformation rely on a delicate balance between liquid crystal order, field properties and network viscoelasticity.
| Original language | English |
|---|---|
| Article number | 3501 |
| Number of pages | 9 |
| Journal | Nature Communications |
| Volume | 10 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 5 Aug 2019 |
Funding
The research of H.M.v.d.K. and S.A.S. forms part of the research programme of the Dutch Polymer Institute (DPI), projects #781 and #913ft16. The work of J.B. was carried out as part of a project of the Institute for Sustainable Process Technology: Controlling Multi Phase Flow (WP-30-01). The contribution of D.J.B. was supported by the European Research Council with the ERC Advanced Grant 66999 (VIBRATE). The work of D.L. is part of the NWO VENI research programme with project number 15135, and that of J.S. of the NWO VIDI research programme with project number 723.016.001. Merck is acknowledged for providing ITO IDE.