Synthesis, mesomorphic and photo-switching behaviours of novel azobenzene chiral liquid crystals containing (-)-menthyl

ABSTRACT

A new series of chiral liquid crystal, Mt4AZOnAB (n = 2–18), containing a multi-chiral centre menthyl and an azobenzene moiety connected with a flexible butanedioyloxy and a varying length of alkanoyloxy in a terminal chain were designed and synthesised. The thermal properties and optical textures were investigated by differential scanning calorimetry and polarising optical microscopy. Selective reflection of the CLCs was measured by ultraviolet/visible spectrometer. Their photo-switching properties were well-demonstrated by UV irradiation. All CLCs show characteristic of selective reflection in heating stage and BPI/II texture in cooling course. Before and after irradiation, CLCs undergoes a transition from oily streak texture to focal conic texture; however, BPI/II texture in cooling stage shows a reversible phase transition.

Graphic Abstract

KEYWORDS:

• Menthol
• chiral liquid crystal
• blue phase
• azobenzene
• selective reflection
• photo-switching

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

This work was supported by the National Natural Science Foundation of China (U1708258) and the Fundamental Research Funds for the Central Universities (N180705004).