Monte Carlo simulations using the dipolar Gay-Berne model: effect of terminal dipole moment on mesophase formation

Ferroelectric and Structured Phases from Polar Tapered Mesogens

“…Moreover, we have found that the polar phase is stable even when an axial dipole of strength corresponding to about 0.8 D is present, making it a ferroelectric nematic. It is clear that the strength of the dipole can affect the phase stability [11] and indeed, when a permanent dipole has been added to rod shaped GB models, important modifications have been observed for the molecular organization [12,13,13,14,15]. The effect of a dipole on mesophase stability depends on its position, orientation and strength, so that a detailed analysis is normally required.…”

Influence of Longitudinal Dipole on Mesophase Formation via Computer Simulation

“…The positional order of the dipole is higher than that of the center-of-mass for the terminal dipolar system. This was also clearly shown in the longitudinal pair correlation [26]. Therefore, the position of the dipole influences the layer formation.…”

“…Simulations for the system established that the dipole near the end of a molecule caused a shift in the nematic-isotropic transition toward a higher temperature [26]. It is demonstrated in Figure 2 that the dipolar Gay-Berne model can qualitatively account for the behavior of the transition temperature for real compounds, for example, the phenylpyrimidine series [34, 351.…”

“…The difference in structures formed accounts for the reason why the strong dipolar systems resist crystallization. Inspection of the snapshots shows that no polarization is observed within a layer as well as in the smectic phase on the whole [26]. Although dipole direction for the system with p* = 1.0 is shown to be random, small clusters made up of molecules having the same direction of dipole are formed for the system with p* = 1.5.…”

“…In addition, the preliminary results of the system composed of molecules with the longitudinal dipole located at the terminal position in a molecule have been published about transition behavior and structure, mainly in a smectic phase [26]. In this paper we report the results of the terminal longitudinal dipolar system on the analysis of the microstructure within a layer in the smectic and crystal phases and of the microstructure of the nematic and isotropic phases in detail.…”