Search

The noise level in a pyroelectric device and therefore the sensitivity is dictated mainly by the dielectric losses in pyroelectric materials. An annealing procedure has been developed that reduces the dielectric loss significantly. The procedure consists of subjecting the ferroelectric liquid crystal sample to an electric field in the isotropic phase and cooling it into the smectic phase at a certain rate. After measurement of the dielectric parameters, the sample is reheated into the isotropic phase and then cooled again at a slower rate into the smectic phase. The entire process is repeated for successively slower cooling rates. We present the results of this annealing treatment and explain the origin of this phenomenon. [ABSTRACT FROM AUTHOR]

Two new ferroelectric liquid crystals, 4-[(S)-1-(ethoxycarbonyl)]ethyl 4-[4-(9-decenyloxy)biphenyl]azobenzoate (10) and its ester analogue 4-[(S)-1-(ethoxycarbonyl)]ethyl {[4-(9-decenyloxy)]biphenyl-4'-yl}carbonyloxybenzoate (17), and side chain polysiloxane copolymers and terpolymers containing various amounts of 10 and 17 as mesogenic side groups have been synthesized. Their mesomorphic and physical properties have been characterized. Both 10 and 17 exhibit isotropic, SmA*, SmC*, and Sm(I or F)* phases. The copolymer with 17 as the mesogenic group and terpolymers having low content of the azo compound 10 show a SmC* phase over a large temperature range down to room temperature. The copolymer with the azo compound 10 as the mesogenic group is amorphous. [ABSTRACT FROM AUTHOR]

This article presents a preface to the journal "Ferroelectrics," published as of November 1, 2002. It constitute research papers presented at the 8th International Conference on "Ferroelectric Liquid Crystals," held at Washington D.C. in August 2001. These papers cover a variety of topics related to the field. The conference was held at Georgetown University in Washington D.C. and was attended by 220 participants from 25 countries.