The influence of core fluorination on the phase behaviour of rod-like mesogens

ABSTRACT

The effect of core fluorination on the mesomorphic properties of rod-like Schiff base-derived liquid crystalline materials was reported. For this purpose, two new series of laterally fluorinated Schiff base liquid crystals are synthesised and investigated in detail. The two series differ from each other’s in the length of the terminal alkoxy chain attached to one end of the aromatic core, where in the first series an octyloxy chain is used and in the second series it is replaced by a longer dodecyloxy chain. At the other end in both series of compounds, in addition to the nonsubstituted end (X = H) four different substituents were used (X = CH₃O, C₆H₁₃O, CH₃ and F). The molecular structures of all synthesised compounds were confirmed using different spectroscopic techniques. The molecular self-assembly was investigated using differential scanning calorimetry (DSC) and polarised optical microscope (POM). Depending on the length of terminal alkoxy chain at one end and nature of the substituent X at the other end, different types of mesophases were observed, including nematic and two different types of smectic phases.

GRAPHICAL ABSTRACT

KEYWORDS:

• Liquid crystals
• Schiff base
• nematic phase
• fluorination
• smectic phase

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data presented in this study are available on request from the corresponding author.

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02678292.2023.2200264

Additional information

Funding

Authors extend their appreciation to, Taibah University, represented by the Deanship of Scientific Research, for funding this project No. (RC-442/13). M. Alaasar acknowledges the German Research Foundation (DFG) for the financial support [AL2378/1-1, 424355983].