Acetylene-containing highly birefringent rod-type reactive liquid crystals based on 2-methylhydroquinone

ABSTRACT

New highly birefringent reactive liquid crystal materials based on the 2-methylhydroquinone core were designed and synthesised. Rod-type liquid crystal compounds bearing photo-crosslinkable reactive group of acryloyl, methacryloyl, cinnamoyl, furylacryloyl group were synthesised by introducing acetylene groups via Sonogashira coupling to obtain high birefringence, and lateral groups such as fluoro and methyl to adjust the temperature of the liquid crystal phase. The synthesised compounds were characterised using nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis. In addition, their thermal behaviour was investigated using differential scanning calorimetry and polarised optical microscopy. After aligning the synthesised compounds, liquid crystal films were prepared by photo-irradiation. Photo-elastic modulator results showed that the obtained liquid crystal films had high birefringence (Δn) values of 0.32–0.40.

GRAPHICAL ABSTRACT

KEYWORDS:

• Liquid crystal
• high birefringence
• reactive LC
• methylhydroquinone

Acknowledgments

This work was supported by the Technology Innovation Industrial Program funded by the Ministry of Trade, Industry and Energy [10052667, Korea] and the National Research Council of Science and Technology for Creative Convergence Research Project under the Contract No. SKM1509 and KRICT Project No. KK-1602-D00.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

This work was supported by the Technology Innovation Industrial Program funded by the Ministry of Trade, Industry and Energy [10052667, Korea] and the National Research Council of Science and Technology for Creative Convergence Research Project under the Contract No. SKM1509 and KRICT Project No. KK-1602-D00.