The results presented are part a research program financed by the Dutch Polymer Institute (DPI), project no 775.
Self-assembled Dynamic 3D Fingerprints in Liquid-Crystal Coatings Towards Controllable Friction and Adhesion†
Article first published online: 11 MAR 2014
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Volume 126, Issue 18, pages 4630–4634, April 25, 2014
How to Cite
Liu, D. and Broer, D. J. (2014), Self-assembled Dynamic 3D Fingerprints in Liquid-Crystal Coatings Towards Controllable Friction and Adhesion. Angew. Chem., 126: 4630–4634. doi: 10.1002/ange.201400370
- Issue published online: 25 APR 2014
- Article first published online: 11 MAR 2014
- Manuscript Received: 13 JAN 2014
- Dutch Polymer Institute (DPI). Grant Number: 775
- Dynamische Oberflächen;
Chiral-nematic polymer network coatings form a “fingerprint” texture through self-assembly. For this purpose the molecular helix of the coating is oriented parallel to the substrate. The coating has a flat surface but when actuated by light in the presence of a copolymerized azobenzene compound, 3D fingerprint structures appear in the coating. The helix forms protrusions at the positions where the molecules are aligned parallel to the surface and withdraws at the positions where the orientation is perpendicular. This process proceeds rapidly and is reversible, that is, the fingerprint-shaped protrusions disappear when the light is switched off. The texture in the on-state resembles that of a human fingerprint and is used to manipulate the gripping friction of a robotic finger. The friction coefficient drops by a factor of four to five when the fingerprint switched on because of reduced surface contacts.