H-2-NMR and SAXS of a ferroelectric liquid crystal: unwinding of the ferroelectric chiral helix by high magnetic fields

H-2-NMR in three different magnetic fields and small angle X-ray scattering (SAXS) are employed to investigate the orientational order, molecular orga nisation and phase transitions of the chiral smectic liquid crystal (-)-(S) -[4-(2-methylbutyloxycarbonyl)phenyl] 4-n-heptyl-biphenyl-carboxylate (MBHB ) suitably deuterated for H-2-NMR measurements. Unwinding of the ferroelect ric chiral helix by high magnetic fields is observed and discussed. Tilt an gle values are obtained with the two different techniques and compared. The results show the importance of molecular conformation for the structural p roperties of this mesogen. (C) 2001 Elsevier Science B.V. All rights reserv ed.