ABSTRACT
A series of new cyclic siloxane side-chain liquid crystal oligomers containing chiral (-)-menthyl monomer (M1) and achiral benzene methyl ester monomer (M2), denoted as O1–O4, were successfully synthesised. Their chemical structures were confirmed by FT-IR and 1H NMR spectra. Phase transition behaviours and phase structures were investigated by differential scanning calorimetry (DSC) and polarised optical microscopy (POM). Bragg-selective reflection spectra were measured by ultraviolet/visible spectrometer (UV/Vis). The glassy oligomers with bright colours at room temperature were obtained by thermal quenching treatment with liquid nitrogen (liquid Nr). The reflection colours were adjusted into visible light region by adjusting the chiral monomer content (XM1*) in oligomers. The glassy oligomers have shown good thermal stability at room temperature for more than 1 year.
Graphical abstract
Disclosure of potential conflicts of interest
No potential conflict of interest was reported by the author(s).