Theoretical approach to study the effect of free volumes on the physical behavior of polymer stabilized ferroelectric liquid crystal molecules

Abstract

It was clearly indicative that the polymer chains make a tremendous interaction with the tilt angle in case of a polymer stabilized ferroelectric liquid crystal (PSFLC). After suitable consideration of such interaction, we expanded the Landau free energy for a PSFLC system. We theoretically demonstrated the effect of free volumes, which expected to create bulk self-energy, on the physical functionalities of a PSFLC system. Then we obtained spontaneous polarization, tilt angle, rotational viscosity and dielectric constant strongly correlated with the assumed interactions. We also observed a shift of transition temperature highly influenced by this interaction between polymer network and liquid crystal molecules. A microscopical picture of this polymer-liquid crystal interaction is provided in view of the free volume charge density present in the composite system.

Poisson–Boltzmann equation and electro-convective instability in ferroelectric liquid crystals: a mean-field approach

“…This produces more counter-ions and co-ions in the medium, which results into a strong crowding effect around each of the molecular cores. Thus, the effective charge density is increased in the medium, as shown in equation (7). These ions further reduce the long-range coulombic interactions into local ones through overscreening.…”

“…One more point needs further clarification. The hypersusceptibility in the modified PB equation equation (7) indicates that the medium responds to the charges (ions and polarization charges) in a spatially nonlocal manner. The higher-order gradients in φ confirm the complexity of spatial dispersion in our system.…”

“…The higher-order gradients in φ confirm the complexity of spatial dispersion in our system. Therefore, additional boundary conditions are required to solve equation (7). The problem of additional boundary conditions has been considered extensively in the literature [32][33][34], but no general method of obtaining this boundary condition is available.…”

“…Both of these instabilities are detrimental to the prospect of commercializing FLCs in display activities. The first problem is adequately addressed with the help of polymer stabilization [7,8], but the second problem is somewhat complex and needs more exploration. Impurities found in FLCs are mainly in the form of foreign or host ions that are either created due to the host molecular dissociations or injected during the fabrication process of the sample.…”