Discotic Liquid Crystals in Nanoporous Solids: From the Structure and Dynamics to Local Charge Transport

• Applicants: Professor Dr. Patrick Huber; Professor Dr. Andreas Schönhals
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 282247454

• Final Report Year: 2019

Final Report Abstract

The main scientific achievements of our project are the following: • First experimental evidence of sequential circular concentric layer formation and resulting quantized changes in the optical properties of discotic-LC-infused nanoporous silica as a function of temperature (birefringence and x-ray diffraction experiments). • Documentation of a pore-size and pore-wall grafting-dependent transition from radial to axial columnar growth by optical birefringence, X-ray diffraction and dielectric spectroscopy. • Comprehensive mapping of the thermotropic phase behavior as a function of pore size, pore-wall grafting and temperature. • Proof of adjustable optical and dielectric anisotropy of the soft-hard hybrid materials by optical birefringence and dielectric spectroscopy, respectively. With regard to the adjustable optical anisotropy of LC-filled nanoporous solids we envision potential applications of these hybrid materials in the emerging field of photonic metasurfaces. We would like to mention that during the course of this project we established a collaboration with the research group of Marco G. Mazza (Max-Planck Institute of Self-Organization and Dynamics, Göttingen) with respect to Monte Carlo simulation of confined discotic LCs. Moreover, we started a collaboration with Prof. Sabine Laschat of the Chemistry Department at Stuttgart University. She provided ionic discotic liquid crystals synthesised in her group. This joined work was the base for a successful application for a new DFG research grant on ionic liquid crystals.

Publications

• Discrete supermolecular ring assembly: From nanoscale physics to metamaterial science. Photon Science 2018. Highlights and Annual Report (DESY) 24 (2018)
  K. Sentker and P. Huber
  
• Dynamics and ionic conductivity of ionic liquid crystals forming a hexagonal columnar mesophase. Phys. Chem. Chem. Phys. 20, 5626 (2018)
  A. Yildirim, P. Szymoniak, K. Sentker, M. Butschies, A. Bühlmeyer, P. Huber, S. Laschat, and A. Schönhals
  
• Quantized self-assembly of discotic rings in a liquid crystal confined in nanopores. Phys. Rev. Lett. 120, 067801 (2018)
  K. Sentker, A. W. Zantop, M. Lippmann, T. Hofmann, O. H. Seeck, A. V. Kityk, A. Yildirim, A. Schönhals, M. G. Mazza, and P. Huber
  
• Collective orientational order and phase behavior of a discotic liquid crystal under nanoscale confinement. Nanoscale Adv. 1, 1104 (2019)
  A. Yildirim, K. Sentker, G. J. Smales, B. R. Pauw, P. Huber, and A. Schönhals
  
• Multiple glassy dynamics in dipole functionalized triphenylene-based discotic liquid crystals revealed by broadband dielectric spectroscopy and advanced calorimetry – assessment of the molecular origin. Phys. Chem. Chem. Phys. 21, 18265 (2019)
  A. Yildirim, A. Bühlmeyer, S. Hayashi, J. C. Haenle, K. Sentker, C. Krause, P. Huber, S. Laschat, and A. Schönhals
  
• Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials. Nanoscale (2019)
  K. Sentker, A. Yildirim, M. Lippmann, A. W. Zantop, F. Bertram, T. Hofmann, O. H. Seeck, A. V. Kityk, M. G. Mazza, A. Schönhals, and P. Huber