Electrooptic properties of the ferroelectric smectic C phase induced by chiral dopants in HOBA and OOBA

A ferroelectric smectic C state was induced in 4-n-octyloxybenzoic acid (OOBA) and 4-n-heptyloxybenzoic acid (HOBA) by the chiral dopants-cholesteryl benzoate (CB) and DOBAMBC—M₁ and M₂ mixtures respectively. A strong electrooptic effect was found for a DC electric field in the ferroelectric state of the M₁ mixture stabilized by the boundaries. This effect is characterised by six increasing electric field thresholds (E⁽¹⁾_th-E⁽⁶⁾_th), where drastic textural and colour changes occur. The electrooptic responses in AC electric field for the two mixtures are discussed. A qualitative model to explain the observed phenomenon is presented.