The Langmuir and Langmuir-Blodgett (LB) techniques have been applied in a novel approach to build structurally well-ordered, oriented, and organized assemblies of water-soluble single-wall carbon nanotubes (ws-SWCNTs) at the air/water and air/solid interfaces. The SWCNTs were rendered hydrophilic by complexing them with a quenched polyelectrolyte. We observed that the ws-SWCNT concentration at the air/water interface increases with time condensing into different patterns, among which are isolated soap-froths, rings, and the aggregation of cumuli-like 2D-structures. These patterns were recorded at different compression-expansion stages by Brewster angle microscopy (BAM). From the isotherm measurements, we are able to determine the diffusion process by which ws-SWCNT concentration builds up at the water surface. The corresponding LB films were very stable and could be transferred onto mica substrates easily. Atomic force microscopy (AFM) images revealed that the morphology of these films is surface-pressure dependent, and aligned structures with a nematic-like order formed closely packed mono- or multilayer films. The assembly of 2D-nanostructures by means of this approach offers a great potential for emergent technological applications using modified water-soluble SWCNTs.
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http://dx.doi.org/10.1021/jp063220t | DOI Listing |
Langmuir
July 2024
Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznan, Poland.
The organization of metallic nanoparticles into assembled films is a complex process. The type of nanoparticle stabilizing ligand and the method for creating an organized layer can profoundly affect the optical properties of the resulting nanoparticle assembly. Investigations of the ligand structure and nanoparticle interactions can provide a greater understanding of the design of the assembly process and the quality of the resulting materials.
View Article and Find Full Text PDFBiophys Chem
May 2023
Centre for Nano and Soft Matter Sciences, Bengaluru 562 162, India. Electronic address:
Azobenzene liquid crystalline (ALC) ligand contains a cholesteryl group linked to an azobenzene moiety through a carbonyl dioxy spacer (C7) and terminated with an amine group as a polar head. The phase behaviour of the C7 ALC ligand at the air-water (A-W) interface is investigated employing surface manometry. The surface pressure-area per molecule isotherm shows that C7 ALC ligand exhibit two different phases following the phase sequence viz.
View Article and Find Full Text PDFSoft Matter
February 2023
Department of Physics, Indian Institute of Technology Patna, Patna, India.
Understanding and control of molecular alignment at the nanoscale in self-assembled supramolecular structures is a prerequisite for the subsequent exploitation of molecules in functional devices. Here, we have clarified the surface-pressure induced molecular nanoarchitectures in a monolayer of a heterocoronene-based discotic liquid crystal (DLC) at air-water and air-solid interfaces using surface manometry, real-time Brewster angle microscopy, and real-space atomic force microscopy (AFM). Chloroform-spread DLCs at a concentration of ∼108 μM exhibit floating domains at the air-water interface comprising small aggregates of edge-on stacked molecules interacting peripheral alkyl chains.
View Article and Find Full Text PDFLangmuir
September 2021
Centre for Nano and Soft Matter Sciences, Shivanapura, Bengaluru 562 162, India.
J Phys Chem B
April 2021
Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.
Phase-separated monolayers of 10,12-pentacosadiynoic acid and perfluorotetradecanoic acid can be photopolymerized to produce micrometer-sized, fluorescent polydiacetylene fibers at the air-solid interface. The photopolymer fibers were not uniformly fluorescent but rather showed a series of fluorescent spots along their lengths. The spots exhibited the classic properties of single-molecule fluorescence emission, including diffraction-limited size and fluorescence intermittency ("on-off blinking").
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