Investigation of crystallization kinetics and its relationship with molecular dynamics for chiral fluorinated glassforming smectogen 3F5HPhH6

Abstract

Glass transition of the antiferroelectric hexatic smectic phase is reported for the 3F5HPhH6 compound. The relationship between the cold crystallization kinetics and the molecular dynamics is determined.

On relaxation and vibrational dynamics in the thermodynamic states of a chiral smectogenic glass-former

“…According to Tanaka, 41 the fragile glass-formers should have a higher tendency for cold crystallization than strong ones. A similar value of m f was obtained for 3F7HPhH7 30 and 3F5HPhF4 (abbreviated as 3F5BFBiHex) 6 liquid crystals, and smaller values were indicated for the 3F7HPhF6 42 and 3F5HPhH6 43 compounds.…”

“…The coexistence of both processes, P H and P L in the phase, was also observed in other compounds with a similar molecular structure. 30,43,50,51 The third process (interpreted as the α-process) is recorded in the high frequency range at only a few temperatures upon slow cooling, i.e. , close to melt crystallization of the sample.…”

Molecular Dynamics and Kinetics of Isothermal Cold Crystallization in the Chiral Smectogenic 3F7FPhH6 Glassformer

“…Finally, the 3F5HPhH6 compound (m = 5, X 1 = H, X 2 = H, r = 6) [60], from the same series as 3F7HPhH6 but with a shorter -C m H 2m -chain and slightly higher fragility m f = 89, shows a much faster cold crystallization despite possessing two crystal phases. However, in 3F5HPhH6 there is a rather direct Cr2 → Cr1 transition, without the previous melting of the Cr2 phase as was observed here for 3F7HPhH6.…”

Investigation of Chiral Smectic Phases and Conformationally Disordered Crystal Phases of the Liquid Crystalline 3F5FPhH6 Compound Partially Fluorinated at the Terminal Chain and Rigid Core

“… 13 , 14 Three of them are confirmed glassformers: 3F5HPhF4 and 3F5HPhF6 exhibit the vitrified SmC A * phase 9 , 10 and 3F5HPhH6 and 3F5HPhH7 exhibit the vitrified hexatic SmX A * phase, which is either SmI A * or SmF A *. 12 − 14 For 3F5FPhF6, the vitrification of the SmC A * phase has not been shown explicitly yet, but it is implied by a very low crystallization rate on cooling. 11 The results from ref 10 − 12 show that the 3F m X 1 PhX 2 r compounds with m = 5 and r = 6 have a tendency to the glass transition of the chiral smectic phase for various fluorosubstitutions of the benzene ring, either both at the X 1 , X 2 positions, only at the X 2 position, or with no F atoms in the benzene ring.…”

“…45°) enables the perfect dark state in a display. 7 , 8 The 3F m X 1 PhX 2 r compounds with m = 5 studied in details are 3F5HPhF4, 9 3F5HPhF6, 10 3F5FPhF6, 11 3F5HPhH6, 12 and 3F5HPhH7. 13 , 14 Three of them are confirmed glassformers: 3F5HPhF4 and 3F5HPhF6 exhibit the vitrified SmC A * phase 9 , 10 and 3F5HPhH6 and 3F5HPhH7 exhibit the vitrified hexatic SmX A * phase, which is either SmI A * or SmF A *.…”