Gelation and helical ribbon formation in the B 4 phase consisting of bent-core molecules

Bent-core materials exhibiting the B4 phase, when dissolved in organic solvents, formed gels with helical ribbons made of molecular monolayers and bilayers, whereas strongly deformed stacks of several layers were found in the bulk samples. The width and pitch of the helical filaments both increased with terminal chain elongation. It was also found that bulk samples were optically active, in contrast to the corresponding gels, which lacked optical activity. The optical activity of samples originated from the internal structure of the crystal layers rather than from the helicity of the filaments. A theoretical model successfully predicts these behaviors.