Abstract
Supramolecular nanotubes prepared through macrocycle assembly offer unique properties that stem from their long-range order, structural predictability, and tunable microenvironments. However, assemblies that rely on weak non-covalent interactions often have limited aspect ratios and poor mechanical integrity, which diminish their utility. Here pentagonal imine-linked macrocycles are prepared by condensing a pyridine-containing diamine and either terephthalaldehyde or 2,3,5,6-tetrafluoroterephthalaldehyde. Atomic force microscopy and synchrotron in solvo X-ray diffraction demonstrate that protonation of the pyridine groups drives assembly into high-aspect ratio nanotube assemblies. A 1 : 1 mixture of each macrocycle yielded nanotubes with enhanced crystallinity upon protonation. UV-Vis and fluorescence spectroscopy indicate that nanotubes containing both arene and perfluoroarene subunits display spectroscopic signatures of arene-perfluoroarene interactions. Touch-spun polymeric fibers containing assembled nanotubes prepared from the perhydro- or perfluorinated macrocycles exhibited Young's moduli of 1.09 and 0.49 GPa, respectively. Fibers containing nanotube assemblies reinforced by arene-perfluoroarene interactions yielded a 93% increase in the Young's modulus over the perhydro derivative, up to 2.1 GPa. These findings demonstrate that tuning the chemical composition of the monomeric macrocycles can have profound effects on the mechanical strength of the resulting assemblies. More broadly, these results will inspire future studies into tuning orthogonal non-covalent interactions between macrocycles to yield nanotubes with emergent functions and technological potential.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2475-2480 |
| Number of pages | 6 |
| Journal | Chemical Science |
| Volume | 13 |
| Issue number | 8 |
| DOIs | |
| State | Published - Feb 28 2022 |
Funding
E. K. R was supported by the Department of Energy (DOE) under grant no. (DE-SC0019356). M. L. B was supported by the National Science Foundation (NSF) under Grant No. (DMR 1507420). M. J. S was supported by the NSF through the Graduate Research Fellowship Program (GRFP) under Grant No. (DGE-1842165). M. J. S. is partially supported by the Ryan Fellowship and the International Institute for Nanotechnology. A. M. E. was supported by the NSF through the GRFP under Grant No. (DGE-1324585). This work made use of the Integrated Molecular Structure Education and Research Center (IMSERC) at Northwestern University, which has received support from the NSF (CHE-1048773), the So\uE09D and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF; NNCI-1542205), the State of Illinois, and the International Institute for Nanotechnology (IIN). This work also made use of the Scanned Probe Imaging and Development (SPID), and the Electron Probe Instrumentation Center (EPIC), facilities of Northwestern University's Atomic and Nanoscale Characterization Experiment Center (NUANCE), which has received support from the So\uE09D and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF; ECCS-1542205). This work was also supported by the North-western University Keck Biophysics Facility and a Cancer Center Support Grant (NCI CA060553). Parts of this work were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS) at Argonne National Lab. This research used resources of the Advanced Photon Source and the Center for Nanoscale Materials, both U.S. Department of Energy (DOE) Office of Science User Facilities operated for the DOE Office of Science by Argonne National Laboratory under Grant No. (DGE-1324585).
ASJC Scopus subject areas
- General Chemistry