Distinct differences in the nanoscale behaviors of the twist-bend liquid crystal phase of a flexible linear trimer and homologous dimer

Michael R. Tuchband, Daniel A. Paterson, Mirosław Salamończyk, Victoria A. Norman, Alyssa N. Scarbrough, Ewan Forsyth, Edgardo Garcia, Cheng Wang, John M. D. Storey, David M. Walba, Samuel Sprunt, Antal Jákli, Chenhui Zhu, Corrie T Imrie, Noel A. Clark

Research output: Contribution to journalArticlepeer-review

60 Citations (Scopus)
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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 languageEnglish
Pages (from-to)10698-10704
Number of pages7
JournalProceedings of the National Academy of Sciences of the United States of America
Volume116
Issue number22
Early online date14 May 2019
DOIs
Publication statusPublished - 28 May 2019

Bibliographical note

This work was supported by National Science Foundation Materials Research Science and Engineering Center Grant DMR-1420736 and Grant DMR-1307674. M.R.T. acknowledges support from the Advanced Light Source Doctoral Fellowship in Residence offered by Lawrence Berkeley National Laboratory. M.S. acknowledges the support of the US National Science Foundation I2CAM International Materials Institute Award, Grant DMR-1411344. We acknowledge use of beamlines 11.0.1.2 and 7.3.3. of the Advanced Light Source supported by the Director of the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under Contract DE-AC02-05CH11231.

Keywords

  • Liquid crystal
  • Twist-bend nematic
  • trimer
  • Heliconical structure
  • RSoXS
  • Trimer
  • Heliconical
  • Twist–bend nematic

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