Evidence of tilt angle in an 8CB–10CB mixture

EPR spectra using perdeuterated 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxy as spin probe on a mixture of p-n-octyl-p′-cyanobiphenyl and p-n-decyl-p′-cyanobiphenyl at a 0.30106 mole fraction for p-n-decyl-p′-cyanobiphenyl revealed the existence of a tilt angle that has been attributed to the longer p-n-decyl-p′-cyanobiphenyl molecules. Temperature control to within ±0.01°C revealed the existence of two-phase regions across the smectic A-to-nematic and the nematic-to-isotropic transitions which point to first-order transitions.