Induced anticlinic ordering and nanophase segregation of bow-shaped molecules in a smectic solvent

Recent experiments indicate that doping low concentrations of bent-core molecules into calamitic smectic solvents can induce anticlinic and biaxial smectic phases. We have carried out Monte Carlo simulations of mixtures of rodlike molecules (hard spherocylinders with length/breadth ratio L-rod/D = 5) and bowshaped molecules (hard spherocylinder dimers with length/breadth ratio L-ban/D = 5 or 2.5 and opening angle psi). We find that a low concentration (3%) of L-ban/D = 5 dimers induces anticlinic (SmCA) ordering in an untilted smectic (SmA) phase for 100degrees less than or equal to psi < 150 degrees. For L-ban/D = 2.5, no tilted phases are induced. However. with decreasing psi we observe a sharp transition from intralamellar nanophase segregation (bow-shaped molecules segregated within smectic layers) to interlamellar nanophase segregation (bow-shaped molecules concentrated between smectic layers) near psi = 130 degrees.