Mesomorphic, structural, electro-optic and dynamic properties of lactic acid derivative and its selectively deuterated isotopomers by means of electro-optics, SAXS, ²H-NMR and neutron spin-echo spectroscopy

ABSTRACT

In this work, we present the synthesis of two analogues of a lactic acid derivative selectively deuterated on phenyl and biphenyl moieties together with a detailed investigation of their properties within the Twist Grain Boundary smectic A* (TGBA*), the ferroelectric Smectic C* (SmC*) and the crystal E phases. The main structural features of the two liquid crystalline phases, namely TGBA* and SmC* phases, were determined by polarising optical microscopy, differential scanning calorimetry, electro-optical techniques, Small Angle X-ray Scattering (SAXS) and ²H Nuclear Magnetic Resonance (²H NMR) measurements. Preliminary results from Neutron Spin-Echo (NSE) spectroscopy, a technique rarely applied to study chiral liquid crystalline materials, are reported. The effect of the external magnetic field on the supramolecular structure of the ferroelectric phase was studied by means of ²H-NMR experiments under different external magnetic fields. The supramolecular and orientational ordering properties of this ferroelectric lactic acid derivative and its deuterated homologues are discussed in the frame of actual knowledge in the field of ferroelectric liquid crystal materials.

GRAPHICAL ABSTRACT

KEYWORDS:

• Lactic acid derivative
• ferroelectric liquid crystal
• deuterated chiral liquid crystals
• neutron spin-echo spectroscopy
• Nuclear Magnetic Resonance
• magnetic field

Acknowledgments

This work was partially supported by Operational Programme Research, Development and Education financed by European Structural and Investment Funds and the Czech Ministry of Education, Youth and Sports (Project No. SOLID21 – CZ.02.1.01/0.0/0.0/16_019/0000760). The work was also supported within the program of Large Infrastructures for Research, Experimental Development and Innovation (project No. LM2015050) and project LTT17019 financed by the Ministry of Education, Youth and Sports, Czech Republic. This research was partially supported by the research project of the Czech Science Foundation CSF 19-03564S. Authors thank the COST ACTION IC1208 (“Integrating devices and materials: a challenge for new instrumentation in ICT”) for partial support. We are grateful for the neutron beam time provided by the Institut Laue-Langevin and acknowledge the support provided by the staff at ILL.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the European Cooperation in Science and Technology [COST ACTION IC1208]; Grantová Agentura České Republiky [CSF 19-03564S]; European Structural and Investment Funds and the Czech Ministry of Education, Youth and Sports [No. SOLID21 - CZ.02.1.01/0.0/0.0/16_019/0000760].