Marta WIERZEJSKA-ADAMOWICZ, Mirosława OSSOWSKA-CHRUŚCIEL¹, Jan CZERWIEC, Redouane DOUALI², Christian LEGRAND², Janusz CHRUŚCIEL¹, Monika MARZEC, and Stanisław WRóBEL

Jagiellonian University, Institute of Physics, Reymonta 4, 30-059 Kraków, Poland
¹University of Podlasie, Institute of Chemistry, 3-go Maja 54, 08-110 Siedlce, Poland
²ULCO, LEMCEL, 50 rue F. Buisson, B. P. 717-62228 Calais, France

(Received November 8, 2009; Accepted April 16, 2010)

Smectic B₂ phase of bent-core 1,3-phenylene bis{4-[(4-dodecyloxybenzoyl)sulfanyl]benzoate} (12OSOR) and a mixture 12R9AF have been studied using dielectric and electrooptic methods. 12R9AF is a mixture of bent-core 12OSOR and calamitic chiral MHPSBO9 materials. The B₂ phase of 12R9AF mixture is shifted to lower temperatures by about 10 °C in comparison with pure 12OSOR. Spontaneous polarization of the mixture is comparable with spontaneous polarization of pure compound. Dielectric measurements were done using dielectric spectrometer based on Agilent 4294A impedance analyzer. Dielectric spectra measured with bias field for B₂ phase of 12OSOR and 12R9AF show two well separated relaxation processes.

Key words: bent-core molecules, antiferroelectric phase, spontaneous polarization, electrooptic effects, dielectric relaxation, molecular and collective processes