Regular Article

The European Physical Journal E

, 36:2

Open Access This content is freely available online to anyone, anywhere at any time.

Strongly nonlinear dynamics of ferroelectric liquid crystals

  • W. JeżewskiAffiliated withInstitute of Molecular Physics, Polish Academy of Sciences Email author 
  • , I. ŚliwaAffiliated withInstitute of Molecular Physics, Polish Academy of Sciences
  • , W. KuczyńskiAffiliated withInstitute of Molecular Physics, Polish Academy of Sciences

Abstract

Molecular reorientation processes induced in thin ferroelectric liquid crystal systems by strong alternating external electric fields are studied both by solving numerically the equation of reorientation motion of molecules and by measuring the electro-optic response of thin samples. It is shown that the occurrence of a wide band in nonlinear response spectra above the Goldstone-mode frequency is a consequence of complex partially uncorrelated molecular reorientations enforced within smectic layers by sufficiently high fields of high enough frequencies. Such nonlinear reorientational motions of molecules are argued to have a character of weakly chaotic long-lasting transients, related to almost periodic modulations of the amplitude of rotational oscillations performed by molecules with the field frequency. These modulations have been numerically proved to proceed with lower frequencies than the field frequency and with space-dependent depths of temporal changes. The occurrence of the modulations has experimentally been confirmed by registering distinct contributions to electro-optic response spectra at frequencies less than the running frequency of the applied electric field.

Graphical abstract

http://static-content.springer.com/image/art%3A10.1140%2Fepje%2Fi2013-13002-7/MediaObjects/10189_2013_9816_Fig1_HTML.jpg

Keywords

Soft Matter: Liquid crystals