Surface modification methods and mechanisms in carbon nanotubes dispersion

It is imperative to induce hydrophilicity in intrinsically hydrophobic carbon nanotubes (CNTs) without losing their superior properties for applications that specifically deal with aqueous media. A method for transforming a CNTs sheet from hydrophobic to hydrophilic by treatment with N-methyl-2-pyrrolidone (NMP) is explored. The NMP-treated CNT sheets are assessed based on complementing characterization, and it is concluded that the binding of NMP to a CNTs surface is through noncovalent interaction without the incorporation of defects in CNTs. The induced hydrophilicity in the CNTs sheet is stable for water exposure over a longer duration while it displays a semireversible nature upon heat treatment. The mechanical and electrical properties of the NMP-treated CNTs sheet revealed enhancement in the tensile strength from 221 to 421 MPa while maintaining a good electrical conductivity of ∼1.22 × 104 S/m because of the improved interfacial properties. The hydrophilic CNTs exhibited excellent adsorption capacity for methylene blue dye. The NMP-treated CNTs sheets demonstrated their suitability in flexible hybrid supercapacitor (FHSC) devices with improved electrochemical performance with enhancement in the capacitance from 5.4 to 7.6 F/g and a decrease in the equivalent series resistance from 53 to 34 Ω compared to pristine CNTs-based devices. These solid-state FHSC devices displayed excellent cyclic charge–discharge performance along with robust behavior over thousands of bending cycles without significant performance degradation. The excellent dye removal capability and superior electrochemical performance of the NMP-treated CNTs sheet is a consequence of their improved interface with aqueous media, which is governed by the hydrophilic nature of the CNTs sheet.

Section: Resultsmentioning

confidence: 99%

Facile and Nondestructive Transformation of Intrinsic Hydrophobic Behavior of a Carbon Nanotubes Sheet to Hydrophilic

Pal,

Subhedar

2024

“…For example, the use of sodium dodecyl sulfonate (SDS) and sodium deoxycholate (SDOC) have been widely reported in the literature despite the vast number of other possibilities. 9,10 This obstacle is a direct result of the absence of a universal guide to aid the researcher in exploring the intertwined relationships among the many factors (nanomaterial type, solvent, dispersion method, desired dispersion state, etc.) and identifying possible dispersants.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Due to the countless reported and unreported varieties, most commonly, researchers use dispersants familiar to them or those reported in the literature, which highly reduces the probabilities of using the most appropriate for a specific purpose. For example, the use of sodium dodecyl sulfonate (SDS) and sodium deoxycholate (SDOC) have been widely reported in the literature despite the vast number of other possibilities. , This obstacle is a direct result of the absence of a universal guide to aid the researcher in exploring the intertwined relationships among the many factors (nanomaterial type, solvent, dispersion method, desired dispersion state, etc.) and identifying possible dispersants.…”

Section: Introductionmentioning

confidence: 99%

Machine Learning-Assisted Exploration and Identification of Aqueous Dispersants in the Vast Diversity of Organic Chemicals

Jintoku,

Futaba

2024

Dispersion represents a central processing method in the organization of nanomaterials; however, the strong interparticle interaction represents a significant obstacle to fabricating homogeneous and stable dispersions. While dispersants can greatly assist in overcoming this obstacle, the appropriate type is dependent on such factors as nanomaterial, solvent, experimental conditions, etc., and there is no general guide to assist in the selection from the vast number of possibilities. We report a strategy and successful demonstration of the machine-learning-based "Dispersant Explorer", which surveys and identifies suitable dispersants from open databases. Through the combined use of experimental and molecular descriptors derived from SMILES databases, the model showed exceptional predictive accuracy in surveying about ∼1000 chemical compounds and identifying those that could be applied as dispersants. Furthermore, fabrication of transparent conducting films using the predicted and previously unknown dispersant exhibited the highest sheet resistance and transmittance compared with those of other reported undoped films. This result highlights that, in addition to opening new avenues for novel dispersant discovery, machine learning has a potential to elucidate the chemical structures essential for optimal dispersion performance to assist in the advancement of the complex topic of nanomaterial processing.

“…24,25 Covalent and noncovalent modification of CNT surfaces are the main methods to improve their dispersion. 26 Covalent modification is mainly realized by chemical reactions to introduce groups to generate covalent bonds with reactive double bonds or other oxygen-containing groups on the CNT surface. 27 Noncovalent modifications include π−π bonding interactions, hydrogen bonding interactions, and ionic bonding interactions.…”

Section: Introductionmentioning

confidence: 99%

Caffeic-Acid-Functionalized MWCNTs and PEDOT:PSS Formed Composite Flexible Films with “Reinforced Concrete” Structure for Electrical Heating and EMI Shielding

Liu,

Tian,

Bao

et al. 2024

Nowadays, flexible multifunctional composites are attracting much attention and are practically being used in various emerging electronic devices. However, most composites suffer from the disadvantages of high loadings of conductive fillers, complicated preparation processes, and low energy conversion efficiency. In this article, Caffeic acidmodified multiwalled carbon nanotubes (C-MWCNTs)/poly(3,4-ethylene dioxythiophene):polystyrene sulfonic acid (PEDOT:PSS)/polyimide (PI) composite films (CPFs) were prepared using a simple layer-by-layer deposition method. The "reinforced concrete" structure of the C-MWCNTs/PEDOT:PSS layer ensures high electrical conductivity of the film, while the PI layer provides excellent mechanical properties (72.69 MPa). The composite film exhibits excellent electrothermal response and thermal stability up to approximately 125 °C at 5 V. In addition, the good conductivity of the film provides its electromagnetic shielding effectiveness (32.69 dB). With these advantages, we expect that flexible CPFs will be widely utilized in wearable devices, electromagnetic interference (EMI) shielding applications, and thermal management of personal or electronic devices.