Abstract
We synthesized the liquid crystal dimer and trimer members of a series of flexible linear oligomers and characterized their microscopic and nanoscopic properties using resonant soft X-ray scattering and a number of other experimental techniques. On the microscopic scale, the twist-bend phases of the dimer and trimer appear essentially identical. However, while the liquid crystal dimer exhibits a temperature-dependent variation of its twist-bend helical pitch varying from 100 to 170 Å on heating, the trimer exhibits an essentially temperature-independent pitch of 66 Å, significantly shorter than those reported for other twist-bend forming materials in the literature. We attribute this to a specific combination of intrinsic conformational bend of the trimer molecules and a sterically favorable intercalation of the trimers over a commensurate fraction (two-thirds) of the molecular length. We develop a geometric model of the twist-bend phase for these materials with the molecules arranging into helical chain structures, and we fully determine their respective geometric parameters.
Original language | English |
---|---|
Pages (from-to) | 10698-10704 |
Number of pages | 7 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 116 |
Issue number | 22 |
Early online date | 14 May 2019 |
DOIs | |
Publication status | Published - 28 May 2019 |
Keywords
- Liquid crystal
- Twist-bend nematic
- trimer
- Heliconical structure
- RSoXS
- Trimer
- Heliconical
- Twist–bend nematic