Unusual formation of switchable hexagonal columnar phase by bent-shaped molecules with low bent-angle naphthalene central core and alkylthio tail

The low-angle bent-shaped molecules with 1,7-naphthalene central core and alkylthio tails can form a novel hexagonal columnar phase and a dark B4 phase. The columnar phase has a large two-dimensional hexagonal lattice with edges of 65-75A° and exhibits polar switching with spontaneous polarization along the column axis. Calculated from the density (̃1 g·cm^-3) and unit volume, the number of molecules that are necessary to fill a 4.6-A° stratum of each column were found to be ̃11. Such a large number of molecules can be accommodated only in the tubelike assembly, which may be the first example as formed by the usual bent-shaped molecule with a single alkylthio tail.