Designing, Synthesising and Characterizing Supercomplex Nanostructures Based on Liquid Crystalline Frank Kasper Phases by Molecular Rod Self-assembly
Synthesis and Properties of Functional Materials
Final Report Abstract
Liquid crystals are well known from display (LCD) industry. Their numerous applications are based on the capability of rod-like molecule to align parallel and thus give rise to a long range orientational order. We use rod-like molecules with sticky ends and tethered them with bulky side chains. While the side chains distort the parallel packing of the rods, the sticky ends keep them together, thus leading to the formation of completely new types of liquid crystalline materials with enhanced complexity. Among them the polygonal honeycombs where the rods form the walls, the sticky ends form columns at the edges, thus fusing the polygonal cells to honeycombs; the side chains fill the prismatic cells. A number of new honeycombs involving triangular cells were obtained, among them a dodecagonal supertiling by triangular, rhombic and square cells. Moreover, a new rhombic honeycomb was discovered as a phase at the transition from triangular to square honeycombs and 4 different lattices were found for honeycombs formed by non-regular triangular cells. The cell deformation is attributed to the combined effects of volume adjustment, tilt of the rod-like molecules in the honeycomb walls and chain stiffening at reduced temperature. Increase of the volume of these side chains by increasing their number or by branching disrupts these honeycombs into bundles of 5 to 12 parallel aligned rods which then form networks. Again, the sticky ends keep the molecules together and form polar spheres located at the junctions of these threedimensional networks, being embedded in the continuum formed by the fluid side chains. In this work it was shown that by modification of the length of the molecular rods, the volume and effective length of the side chains, the kind of formed network can be specifically tailored. In total 7 new network structures, 5 of them with cubic symmetry, were discovered; these are the single diamond, the single plumbers Nightmare phase, an open octahedral framework and the Frank Kasper type A15 phase formed by rod-bundles. Two new noncubic three-dimensional networks with Fmmm and P63/m space group were discovered as intermediate phases at the transition between the double diamond and the double gyroid network phases. The reported unique network structures combining sphere packing with networks can be considered as liquid crystalline supramolecular organic frameworks, where the polyaromatic rods are interconnected by the dynamic H-bonding in the glycerol-based spheres acting as linkers, thus being complimentary to metalorganic and covalent organic frameworks (MOFs and COFs) and expanding reticular chemistry from solid-state structures to soft matter. Moreover, the polar spheres can be considered as “superatoms” with a distinct valence, interconnected by the polyaromatic rods as the “bonds”.
Publications
- A Self-Assembled Bicontinuous Cubic Phase with a Single-Diamond Network, Angew. Chem. Int. Ed., 2019, 58, 7375-7379
X. Zeng, S. Poppe, A. Lehmann, M. Prehm, C. Chen, F. Liu, H. Lu, G. Ungar, C. Tschierske
(See online at https://doi.org/10.1002/anie.201902677) - A periodic dodecagonal supertiling by selfassembly of star-shaped molecules in the liquid crystalline state, Comms. Chem., 2020, 3, 70
M. Poppe C. Chen, S. Poppe, F. Liu, C. Tschierske
(See online at https://doi.org/10.1038/s42004-020-0314-1) - Chirality Induction through Nano-Phase Separation: Alternating Network Gyroid Phase by Thermotropic Self-Assembly of X-Shaped Bolapolyphiles, Angew. Chem . Int. Ed., 2020, 50, 2725-2729
C. Chen, R. Kieffer, H. Ebert, M. Prehm, R.-B. Zhang, X. Zeng, F. Liu, G. Ungar, C. Tschierske
(See online at https://doi.org/10.1002/anie.201911245) - Different Modes of Deformation of Soft Triangular Honeycombs at the Sub-5 nm Scale, Adv. Mater., 2020, 2005070
M. Poppe, C. Chen, S. Poppe, C. Kerzig, F. Liu, C. Tschierske
(See online at https://doi.org/10.1002/adma.202005070) - Liquid Organic Frameworks: A Liquid Crystalline 8- Connected Network with Body-Centered Cubic Symmetry, Angew. Chem. Int. Ed., 2020, 59, 20820-20825
C. Chen, M. Poppe, C. Tschierske, F. Liu
(See online at https://doi.org/10.1002/anie.202008784) - Liquid Organic Frameworks: The Single-Network “Plumber’s Nightmare” Bicontinuous Cubic Liquid Crystal, J. Am. Chem. Soc., 2020, 142, 3296-3300
S. Poppe, X. Cheng, C. Chen, X. Zeng, R.-B. Zhang, F. Liu, G. Ungar, C. Tschierske
(See online at https://doi.org/10.1021/jacs.9b11073) - Emergence of uniform tilt and π-stacking in triangular liquid crystalline honeycombs, Chem. Commun., 2021, 57, 5626-5629
M. Poppe, C. Chen, F. Liu, S. Poppe, C. Tschierske
(See online at https://doi.org/10.1039/d1cc02556b) - Tetrahedral Liquid-Crystalline Networks: An A15-Like Frank–Kasper Phase Based on Rod-Packing, Angew. Chem. Int. Ed., 2022, e202203447
C. Chen, M. Poppe, S. Poppe, M. Wagner, C. Tschierske, F. Liu
(See online at https://doi.org/10.1002/anie.202203447) - The Rhombic Honeycomb – A New Mode of Self-Assembly in Liquid Crystalline Soft Matter, Chem. Commun., 2022
A. Saeed, M. Poppe, M.B. Wagner, S. Hauche, C. Anders, Y. Cao, L. Zhang, C. Tschierske, F. Liu
(See online at https://doi.org/10.1039/d2cc01907h)
