MSGP Seminar 3/15/23 Electric Field Induced Surface Instability in a Ferroelectric Nematic Material

PhD student Marcell Máthé, Wigner Research Centre for Physics, Budapest, Hungary


In external fields wide range of surface instabilities can be observed in fluids, like the Rosensweig instability in ferrofluids in presence of magnetic field or the Rayleigh-Taylor cone instability in electric field. After the recent discovery of polar nematic materials [1], which have a ferroelectric nematic phase, an obvious question arises: Can an electric field driven surface instability be observed in these materials? We studied the liquid crystal RM734 that exhibits both a ferroelectric and a normal dielectric nematic phase. We investigated the response of RM734 droplets to electric fields in the nematic and the ferroelectric nematic phase using in-plane and normal electrodes in various geometries. In our experiments on the ferroelectric nematic phase, we observed pattern formation (see Fig. 1) as a consequence of an electric field induced surface instability. We characterize the effect and make FEM simulations to visualize the electric field in the material. As a results of our measurements, we provide a model to explain the basic mechanism of the pattern formation observed in ferroelectric nematic droplets with free surface exposed to electric fields.

Figure 1: Electric field induced pattern formation in a ferroelectric nematic fluid (b).


Acknowledgements: We are thankful to Ewa Körblova and David Walba at University of Colorado at Boulder for providing RM734 for us. Financial support was provided by the grant NKFIH FK125134 and NSF-DMR-1904167.


[1] H. Nishikawa, et al., Adv. Mater. 29, 1702354 (2017); A. Mertelj, et al., Phys. Rev. X 8, 041025 (2018); X. Chen, et al., PNAS 117, 14021 (2020)

In-person Seminar
Wednesday, March 15, 2023
3:20 PM (EST)

POSTED: Wednesday, March 15, 2023 04:52 PM
Updated: Wednesday, March 22, 2023 10:24 AM