Strategies to create organized multicomponent nanostructures composed of discrete, self-sorted domains are important for developing materials that mimic the complexity and multifunctionality found in biological systems. These structures can be challenging to achieve due to the required balance of molecular self-recognition and supramolecular attraction needed between the components. Herein, we report a strategy to construct a two-component nanostructure via a hierarchical assembly process whereby two monomeric building blocks undergo self-sorting assembly at the molecular level followed by a supramolecular association to form a nanofiber-wrapped nanotube. The two molecules self-sorted into respective nanofiber and nanotube assemblies, yet assembly of the nanofibers in the presence of the nanotube template allowed for directed integration into a hierarchical multilayer structure via electrostatic interactions. The fiber-wrapped nanotube co-assembly was characterized using transmission electron microscopy (TEM), atomic force microscopy (AFM) and Förster resonance energy transfer (FRET) between the components. Strategies to co-assemble multicomponent nanostructures composed of discrete, spatially sorted domains with controllable higher level interactions will be critical for the development of novel, functionally competent nanomaterials.
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Ion-Exchange Effects in One-Dimensional Lepidocrocite TiO2: A Cryogenic Scanning Transmission Electron Microscopy and Density Functional Theory Study
One-dimensional lepidocrocite, 1DL, titania, TiO2, is a recently discovered form of this ubiquitous oxide that is of interest in a variety of applications ranging from photocatalysis to water purification, among others. The fundamental building blocks of these materials are snippets (30 nm long) of individual 1DLs that self-assemble into nanobundle, NB, structures. These NBs can then be driven to self-assemble into quasi-two-dimensional, 2D, sheets, films, or free-flowing mesoscopic particles. Here, we use analytical atomic-resolution scanning transmission electron microscopy (STEM) and first-principles density functional theory (DFT) calculations to demonstrate that the arrangement of the neighboring NFs can be altered through ion exchange with Li, Na, and tetramethylammonium hydroxide (TMA) cations. Moreover, using cryogenic electron energy-loss spectroscopy (EELS), we show that the introduction of different ion species results in a change in the local occupancy of the TiO2 t2g and eg orbitals. Both experimental findings are predicted by ground-state energy simulations of two-dimensional lepidocrocite TiO2.
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- Award ID(s):
- 2309396
- NSF-PAR ID:
- 10521555
- Publisher / Repository:
- Materials Data Facility
- Date Published:
- Format(s):
- Medium: X
- Institution:
- University of Illinois - Chicago
- Sponsoring Org:
- National Science Foundation
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