Synthesis and characterization of liquid crystal methyl methacrylic monomers

Springer Science and Business Media LLC - Tập 10 Số 1 - Trang 129-135 - 2024
Olusegun Amos1, Georg H. Mehl1, Rami Adel Pashameah2
1Department of Chemistry, Faculty of Science and Engineering, University of Hull, Hull, UK
2Department of Chemistry, Faculty of Applied Sciences, Umm Al-Qura University, Makkah, Saudi Arabia

Tóm tắt

AbstractThree liquid crystalline monomers were systematically designed, synthesised and characterised. Methyl methacrylic unit was linked to the mesogenic compound, 4′-Undecycloxybiphenyl-4-yl 4-octyloxy-2-(pent-4-en-1-yloxy) benzoate, (Me), using disiloxane, ester and siloxane units respectively. In the first compound, 4′-(undecyloxy)-[1,1′-biphenyl]-4-yl 2-((5-(3-(4-(methacryloyloxy)butyl)-1,1,3,3-tetramethyldisiloxanyl)pentyl)oxy)-4-(octyloxy)benzoate, (M1), the methyl methacrylic unit was linked to the mesogen by disiloxane group, (Si–O–Si), while ester group, (COOC), was used in the second compound, 4′-(undecyloxy)-[1,1′-biphenyl]-4-yl 2-((5-(methacryloyloxy)pentyl)oxy)-4-(octyloxy)benzoate, (M2), and siloxane unit, (Si–O), in the third compound, 4′-(undecyloxy)-[1,1′-biphenyl]-4-yl 2-((5-((4-(methacryloyloxy)butyl)dimethylsilyl)pentyl)oxy)-4-(octyloxy)benzoate, (M3). The introduction of the methyl methacrylic unit caused the melting point of the compounds to reduce with Me melting at 53.3 °C, M1 at −8.1 °C and M2 at −12.5 °C. The three compounds showed characteristic nematic textures when observed under POM and when compared to the mesogenic compound (Me, 71.7 °C), there were remarkable reduction in the clearing points of the compounds, with M1 clearing at 18.6 °C, M2 at 68.8 °C and M3 at 10.3 °C. Finally, there was appreciable increment in the nematic phase range for the compounds when compared to the mesogen, Me, 18.4 °C. The range was 26.7 °C for M1, 81.3 °C for M2 and since there was no observable crystallization point for M3, the range was not determined.

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Amos O (2015) Thesis submitted to University of Hull, UK. Available on https://hydra.hull.ac.uk/assets/hull:13065a/content

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Tập 10 Số 1

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