Interlocking of Single-Walled Carbon Nanotubes with Metal-Tethered Tetragonal Nanobrackets to Enrich a Few Hundredths of a Nanometer Range in Their Diameters

Scalable one-step fabrication of integrated electrode arrays for highly sensitive and portable carbendazim detection

Highly sensitive and portable pesticide residues detection are indispensable for safeguarding food safety and environmental health. Herein, we introduce a one-step vacuum filtration strategy for the scalable production of cobalt-based conjugated coordination polymers (CoCCPs) electrode arrays, utilizing carboxylated single-walled carbon nanotubes (c-SWNTs) as bonding bridges (CoCCPs@c-SWNTs). Due to their abundant active sites and high conductivity, the CoCCPs@c-SWNTs arrays exhibit superior electrochemical performance (e.g., active area, charge transfer capacity, adsorbed charge, etc.) and enhanced electrocatalytic activity for carbendazim (CBZ). Benefiting from the homogeneous and twining interface, the CoCCPs@c-SWNTs arrays also demonstrate good repeatability, reproducibility, and stability (relative standard deviations <5 %). The CoCCPs@c-SWNTs sensor, with a linear range of 0.01-4.0 μM and a detection limit of 1.9 nM, has been successfully employed in tea and strawberry samples. Overall, this novel sensor holds great potential for application in rapid on-site detection of pesticide residues.

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

We have been working with carbon nanotube separation through host-guest chemistry. Herein, a new macrocyclic host molecule, Cu-tethered square nanobrackets, is designed, synthesized and applied to single-walled carbon nanotubes (SWNTs) for their diameter-based separation. The complexation between copper ions and dipyrrin moieties of the nanobracket gives Cu-tethered square nanobrackets, which is confirmed by absorption, Raman and MALDI-TOF mass spectra. Upon extraction of SWNTs with the nanobracket and copper(II), in situ-formed square Cu-nanobrackets are found to interlock SWNTs to disperse them in 2-propanol. The interlocking is confirmed by Raman spectroscopy after thorough washing of the extracted SWNTs. Pristine SWNTs were recovered through demetalation of the interlocked ones along with the nanobracket. Raman and absorption spectroscopies of the extracted SWNTs reveals the diameter enrichment of only several kinds of SWNTs in the diameter range from 0.94 to 1.10 nm among ≈20 kinds of SWNTs from 0.76 to 1.20 nm in their diameter range. The diameter selectivity is supported by the theoretical calculations with the GFN2-xTB method, indicating that the most preferred SWNT diameter for the square Cu-nanobrackets is 1.04 nm.

Automated statistical analysis of raman spectra of nanomaterials

Both at the academic and the industrial level, material scientists are exploring routes for mass production and functionalization of graphene, carbon nanotubes (CNT), carbon dots, 2D materials, and heterostructures of these. Proper application of the novel materials requires fast and thorough characterization of the samples. Raman spectroscopy stands out as a standard non-invasive technique capable of giving key information on the structure and electronic properties of nanomaterials, including the presence of defects, degree of functionalization, diameter (in the case of CNT), different polytypes, doping, etc. Here, we present a computational tool to automatically analyze the Raman spectral features of nanomaterials, which we illustrate with the example of CNT and graphene. The algorithm manages hundreds of spectra simultaneously and provides statistical information (distribution of Raman shifts, average values of shifts and relative intensities, standard deviations, correlation between different peaks, etc.) of the main spectral features defining the structure and electronic properties of the samples, as well as publication-ready graphical material.

Mechanical Interlocking to Unlock the Reinforcing Potential of Carbon Nanotubes

Single-walled carbon nanotubes (SWNTs) present extraordinary mechanical properties, with Youngs' modulus>1 TPa and tensile strength>50 GPa; this makes them ideal candidates as fillers for the reinforcement of polymers. However, the performance of SWNTs in this field has fallen behind expectations. This is due to a combination of imperfect individualization of the SWNTs and poor load transfer from the polymer to the SWNTs. Here, we study the reinforcement of polymers of different chemical nature using mechanically interlocked derivatives of single-walled carbon nanotubes (MINTs). We compare the mechanical properties of fibers made of poly (methyl methacrylate) (PMMA) and polysulfone (PSU) and their composites made with pristine SWNTs, MINTs, and the corresponding supramolecular models. With very low loading of MINTs (0.01 % w/w), improvements of more than 100 % on Youngs Modulus and the tensile strength are observed for both the nonpolar aliphatic PMMA and the very polar aromatic PSU polymers, while pristine carbon nanotubes and the supramolecular nanofillers showed smaller reinforcement. These data, together with our previous report on the reinforcement of polystyrene (nonpolar and aromatic), indicate that derivatization of SWNTs as MINTs is a valid general strategy to optimize the interaction between SWNT fillers and the polymer matrix.

Mechanically interlocked derivatives of carbon nanotubes: synthesis and potential applications

An introduction to mechanically interlocked derivatives of single-walled carbon nanotubes: their main structural features, their potential advantages compared to covalent and supramolecular derivatives, how to synthesize them, and their most promising fields for application.