title: Monolayer Filaments versus Multilayer Stacking of Bent-Core Molecules.
abstract: Bent-core materials exhibiting lamellar crystals (B4 phase), when dissolved in organic solvents, formed gels with helical ribbons made of molecular monolayers and bilayers, whereas strongly deformed stacks of 5-6 layers were found in the bulk samples. The width and pitch of the helical filaments were governed by molecular length; they 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 predicts a strong increase in optical activity as the number of layers in the stack increases and its saturation for few layers, thus explaining the smaller optical activity for gels than for bulk samples. A strong increase and redshift in fluorescence was detected in gels as compared to the sol state.
authors.affiliation: University of Warsaw, Department of Chemistry, ul. Żwirki i Wigury 101, 02-089, Warsaw, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Matraszek
authors.affiliation: University of Warsaw, Department of Chemistry, ul. Żwirki i Wigury 101, 02-089, Warsaw, Poland.
authors.forename: Neha
authors.initials: N
authors.lastname: Topnani
authors.affiliation: Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroska 160, 2000, Maribor, Slovenia.|Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.
authors.forename: Natasa
authors.initials: N
authors.lastname: Vaupotič
authors.affiliation: University of Warsaw, Department of Chemistry, ul. Żwirki i Wigury 101, 02-089, Warsaw, Poland.|Toyota Physical and Chemical Research Institute, 41-1, Yokomichi, Nagakute, Aichi, 480-1192, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Takezoe
authors.affiliation: University of Warsaw, Department of Chemistry, ul. Żwirki i Wigury 101, 02-089, Warsaw, Poland.
authors.forename: Jozef
authors.initials: J
authors.lastname: Mieczkowski
authors.affiliation: University of Warsaw, Department of Chemistry, ul. Żwirki i Wigury 101, 02-089, Warsaw, Poland.
authors.forename: Damian
authors.initials: D
authors.lastname: Pociecha
authors.affiliation: University of Warsaw, Department of Chemistry, ul. Żwirki i Wigury 101, 02-089, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Gorecka
keywords: bent-core molecules; chiral symmetry breaking; gels; helical nanofilaments; liquid crystals