Surface and volume bistability in ferroelectric liquid crystals

We call the bistabifity of ferroelectric liquid crystal (FLC) cells as the surface bistability (SB), if the dispersion part of anchoring energy is responsible for this type of bistabiity. SB was predicted theoretically [1] and investigated experimentally [2-4] .It was shown, that SB there exists in SSFLC cells possessing the bookshelf structure of smectic C layers [2] and SB there exists only in limited region of multidimensional space of cell and driving voltage parameters [3]. Anchoring energy of FLC with solid surface for SB structures is [4]: 102 iO erg / cm2 On the other hand there exists the volume bistability (VB), which have been observed by us recently in thick (15 mkm and more) layers of new FLC compositions [5].VB is a special phenomenon caused only with stereo chemical nature of the FLC composition and quite independent upon surfaces. In this work we would try: to found the physical principle for experimental measurement of an average free energy density of ferroelectrics, -to describe manifestations for both SB and VB, - to compare SB and VB from point of view their free energy parameters.