Hydrogen-bonded LC nanocomposites: characterisation of nanoparticle-LC interactions by solid-state NMR and FTIR spectroscopies

ABSTRACT

Although the molecular-level nanoparticle-liquid crystal (NP-LC) interactions are key for forming stable NP dispersions in LC, characterisation of these interactions is scarce in the literature. Recently, we have developed hydrogen-bonded LC nanocomposites based on mesogenic carboxylic acids and NPs functionalised with hydrogen-bond acceptor/donor groups. Here, we apply solid-state ¹H and ¹³C NMR and Fourier transform infrared spectroscopies to model systems consisting of mixtures of trans-4-n-butylcyclohexanecarboxylic acid (4-BCHA), 4-hexylbenzoic acid (6BA) and 4,4ʹ-bipyridine. The binary mixture, 4-BCHA:6BA, was also studied. The results were compared to monolayer quantities of 6BA and 4-BCHA adsorbed on pyridine functionalised zirconia NPs (ZrO₂-n₃-pyridine) to understand the different effects of the functionalised NPs on the LC properties.

Graphical Abstract

KEYWORDS:

• Hydrogen-bonded liquid crystals
• solid-state NMR
• LC nanocomposites
• nanoparticles

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplementary material can be accessed here.

Additional information

Funding

This research was supported by a Discovery Grant from the National Science and Engineering Research Council (NSERC). B. Guzman Juarez acknowledges financial support from CONACYT (Mexico) and Bourse d’excellence pour étudiants étrangers (FQRNT, Quebec) for Ph.D. scholarship grants.