Polarization modulated orthogonal smectic phases

Polar orthogonal phases of bent-core materials have long been predicted, and a field-induced SmAP$_{F}$ has been reported$^{1}$. We have recently observed a stable SmAP$_{F}$ phase, obtained by design for an asymmetric bent-core mesogen with only one tail$^{2}$. Here we report studies on a similar single-tail bent-core mesogen, W596, which suggest the new material possesses an I-SmAP$_{F}$'-SmAP$_{F}$-Crystal phase sequence on cooling, where the SmAP$_{F}$' phase is similar to the SmAP$_{F}$ phase except that the SmAP$_{F}$' phase is polarization modulated, leading to the formation of layer undulations, evidenced from the 1D periodic line patterns in freeze fracture transmission electron microscopy images, and x-ray reflections in addition to the main smectic layering reflection. Results of polarizing optical microscopy, electro-optic studies, and differential scanning calorimetry will also be presented. [1] Y. Shimbo, et al. PRL 97, 113901 (2006). [2] D. M. Walba, et al. 11th FLC Conference, 2007, p31.