Abstract
Two smectogens being structural analogs with the opposite space orientation of the COO ester group in the molecular core exhibit extremely different tilt angles. A molecular mechanism of the induction of the high optical tilt angle is searched on the basis of extensive investigations of those compounds.
Computer modeling of molecules and investigations of physical parameters of smectic phases were done. Different molecular aggregates forming smectic phases were observed. The size and shape of those aggregates are estimated on the basis of measurements and calculations. The different values of the tilt angles in studied compounds were discussed.
Notes
μ – the magnitude of the molecular dipole moment ,
μx, μy, μz-the x, y, z components of the molecular dipole moment ,
μ⊥ – the perpendicular component of the dipole moment
ϕ – the angle between the dipole moment and short Oz molecular axis,
γ – the angle between the dipole moment and long Ox molecular axis,
β – the angle between rigid molecular core and the chiral part.
Spacing d1 and d2, the tilt angle θE are taken out of the experiment.
The dimmer length of L20 in SmA* was estimated as .
The dimmer length of L20 in SmC* was estimated as .
The dimmer length of L20 in SmH* was estimated as .
The angle of θT in tilted SmH* phase of CO-20 was estimated as θT = .
The spacing of was estimated as
.
The spacing of was estimated as
.