Ferroelectric Nematic and Smectic Liquid Crystals from Tapered Molecules

Computer simulations of hard pear-shaped particles

“…We have found that this case gives an asymmetrical lobe shape which we have found to be consistent with the equivalent surface given by the models of Ref. [1]. Importantly, we note that all three of the PHGO contact functions considered in this way are almost perfectly convex, and, so, should not be prone to the locking-up suffered by the truncated Stone function expansion models simulated in subsection 2.1.…”

“…This indicates that if there is a region of fluid, nematic phase-stability, it lies beyond the pressure values considered here; we have certainly found no evidence that the nematic phase seen in Ref. [1] is preserved when the k = 3 model is stripped of its attractive interactions. From this change of phase behaviour, we infer that, for this system, the presence of attractive interactions affects the local packing of the particles -the attractive wells, being located at r > σ(û i ,û j ,r ij ), provide a means by which the particles can escape from the inter-locked arrangements that dominate the equivalent hard particle system at high densities.…”

“…Indeed, the failure of our hard 8 pear systems to form nematic phases could be taken as an indication that particle shape did not contribute significantly to the mesophase formation processes seen in Ref. [1]. To assess both this and the non-equilibration noted above, we have measured the particle mobility in our systems by computing the mean square displacement…”

Computer simulations of hard pear-shaped particles

“…We have found that this case gives an asymmetrical lobe shape which we have found to be consistent with the equivalent surface given by the models of Ref. [1]. Importantly, we note that all three of the PHGO contact functions considered in this way are almost perfectly convex, and, so, should not be prone to the locking-up suffered by the truncated Stone function expansion models simulated in subsection 2.1.…”

“…This indicates that if there is a region of fluid, nematic phase-stability, it lies beyond the pressure values considered here; we have certainly found no evidence that the nematic phase seen in Ref. [1] is preserved when the k = 3 model is stripped of its attractive interactions. From this change of phase behaviour, we infer that, for this system, the presence of attractive interactions affects the local packing of the particles -the attractive wells, being located at r > σ(û i ,û j ,r ij ), provide a means by which the particles can escape from the inter-locked arrangements that dominate the equivalent hard particle system at high densities.…”

“…Indeed, the failure of our hard 8 pear systems to form nematic phases could be taken as an indication that particle shape did not contribute significantly to the mesophase formation processes seen in Ref. [1]. To assess both this and the non-equilibration noted above, we have measured the particle mobility in our systems by computing the mean square displacement…”

Mesogen polarity effects on biaxial nematics. Centrally located dipoles

“…For these nematics we have not observed any spontaneous formation of ferroelectric phases 51 or even of polar cybotactic clusters, 48 as found, e.g. in some bent-core mesogens where they lead to large field induced biaxiality.…”

Ferroelectric and Structured Phases from Polar Tapered Mesogens

“……”

Computer simulations of hard pear-shaped particles

“…We have found that this case gives an asymmetrical lobe shape which we have found to be consistent with the equivalent surface given by the models of Ref. [1]. Importantly, we note that all three of the PHGO contact functions considered in this way are almost perfectly convex, and, so, should not be prone to the locking-up suffered by the truncated Stone function expansion models simulated in subsection 2.1.…”

“…This indicates that if there is a region of fluid, nematic phase-stability, it lies beyond the pressure values considered here; we have certainly found no evidence that the nematic phase seen in Ref. [1] is preserved when the k = 3 model is stripped of its attractive interactions. From this change of phase behaviour, we infer that, for this system, the presence of attractive interactions affects the local packing of the particles -the attractive wells, being located at r > σ(û i ,û j ,r ij ), provide a means by which the particles can escape from the inter-locked arrangements that dominate the equivalent hard particle system at high densities.…”

“…Indeed, the failure of our hard 8 pear systems to form nematic phases could be taken as an indication that particle shape did not contribute significantly to the mesophase formation processes seen in Ref. [1]. To assess both this and the non-equilibration noted above, we have measured the particle mobility in our systems by computing the mean square displacement…”

Mesogen polarity effects on biaxial nematics. Centrally located dipoles

“…For these nematics we have not observed any spontaneous formation of ferroelectric phases 51 or even of polar cybotactic clusters, 48 as found, e.g. in some bent-core mesogens where they lead to large field induced biaxiality.…”

Ferroelectric and Structured Phases from Polar Tapered Mesogens

“……”

Computer simulations of hard pear-shaped particles

“…We have found that this case gives an asymmetrical lobe shape which we have found to be consistent with the equivalent surface given by the models of Ref. [1]. Importantly, we note that all three of the PHGO contact functions considered in this way are almost perfectly convex, and, so, should not be prone to the locking-up suffered by the truncated Stone function expansion models simulated in subsection 2.1.…”

“…This indicates that if there is a region of fluid, nematic phase-stability, it lies beyond the pressure values considered here; we have certainly found no evidence that the nematic phase seen in Ref. [1] is preserved when the k = 3 model is stripped of its attractive interactions. From this change of phase behaviour, we infer that, for this system, the presence of attractive interactions affects the local packing of the particles -the attractive wells, being located at r > σ(û i ,û j ,r ij ), provide a means by which the particles can escape from the inter-locked arrangements that dominate the equivalent hard particle system at high densities.…”

“…Indeed, the failure of our hard 8 pear systems to form nematic phases could be taken as an indication that particle shape did not contribute significantly to the mesophase formation processes seen in Ref. [1]. To assess both this and the non-equilibration noted above, we have measured the particle mobility in our systems by computing the mean square displacement…”

Mesogen polarity effects on biaxial nematics. Centrally located dipoles

“…For these nematics we have not observed any spontaneous formation of ferroelectric phases 51 or even of polar cybotactic clusters, 48 as found, e.g. in some bent-core mesogens where they lead to large field induced biaxiality.…”

Ferroelectric and Structured Phases from Polar Tapered Mesogens

“……”