Combined light and electric response of topographic liquid crystal network surfaces

Wei Feng, Dirk J. Broer, Danqing Liu (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

An approach is proposed to create robust liquid crystalline polymer coatings that exhibit sensitivity and dynamic reversibility toward multiple external stimuli including UV irradiation and electrical input. This coating spontaneously alters its surface topographic texture and thickness in response to each of these signals. The corresponding deformations are induced by the photo-/electromechanical properties and dielectric anisotropy in the liquid crystal networks through order parameter reduction and anisotropic volume expansions. The deformation proceeds fast within several seconds both for activation and for the relaxation to the initial state upon switching the trigger(s) on and off. Light and electric field can be applied independently to excite the topographies or in a synergistic manner to enhance the deformation amplitude. Upon elimination of the combined light and electric actuating trigger, the relaxation to the initial close to flat state follows a complex pathway. Depending on the elimination order the topographic structure can be rapidly erased or can be kept in a bistable state. The results of this study are relevant for various fields, for instance, switchable controlled friction, controlled adhesion, and release of objects and haptics where they affect human perception both in passive and dynamic manner.

Original languageEnglish
Article number1901681
Number of pages7
JournalAdvanced Functional Materials
Volume30
Issue number2
DOIs
Publication statusPublished - 10 Jan 2020

Funding

This work was supported by European Research Council with the ERC Advanced Grant 66999 (VIBRATE), the framework of the 4TU.High Tech Materials research program “New Horizons in designer materials,” NWO VENI grant 15135. Merck is acknowledged for providing ITO IDE. The authors acknowledge Prof. Michael Wübbenhorst and Alessia Gennaro at KU Leuven for dielectric anisotropy measurement.

FundersFunder number
European Union 's Horizon 2020 - Research and Innovation Framework Programme669991
European Research Council15135, 66999
Katholieke Universiteit Leuven

    Keywords

    • dual-responsive
    • dynamic surface topographies
    • electricity
    • light
    • liquid crystal networks

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