Formation, Structure, and Function of Hydrogenated and Fluorinated Long‐Chain Phosphonate‐Modified Single‐Walled Carbon Nanotubes with Bidentate Bonds

Abstract

The dispersion of hydrophilized single-walled carbon nanotube (SWCNT) in organic solvent, through the modification of its surface by bidentate long-chain phosphonic acid with excellent heat resistance, and its structural characterization, through the formation of a monolayer on the water surface, have been performed. The surface-modified chains were developed by both hydrocarbon-based and fluorocarbon-based modifiers, and the arrangement of the organized films of each modified SWCNT was evaluated. The modified nanotubes were uniformly dispersed in toluene solvent, facilitating the confirmation of its lipophilicity, and spread as a monolayer at the air-water interface. The morphology of the organo-SWCNT monolayer was fibrous. In the Raman spectrum of the modified-SWCNT Langmuir-Blodgett multilayers, the defect-derived D band shifted to lower wavenumbers. The above experimental results confirmed the non-desorptive property of the modifiedbidentate chain. The packing and orientation of the modified chains were evaluated through out-of-plane and in-plane X-ray diffraction and polarized infrared spectroscopy. In addition, the monolayer of organo-SWCNT was densified with a small number of defects by the "repeating compression-expansion method". Furthermore, activation of the lysozyme enzyme from the subphase caused adsorption and immobilization onto organo-SWCNT monolayers. The introduction of SWCNTs to the air-water interface has revealed the potential for nanostructural control and the estimation of interactions between biomolecules.

Immobilization of Trypsin from the Subphase to the Langmuir Monolayer of Fluorocarbon-Modified Single-Walled Carbon Nanotube and Its Activity Maintenance

“…In this case, it is known from Raman shift that there is definitely a certain amount of damage to the conjugated system. 26 However, within the range judged from the Raman spectrum, it cannot be said that the effect is extremely serious on the conjugated system. We have already reported the mechanism of hydrophilic surface modification by phosphonic acid derivatives.…”

Activity Maintenance Characteristics and Protease Adsorption on Langmuir Monolayer of Organo‐Modified Single‐Walled Carbon Nanotubes

“…As discussed in previous studies, the morphology of the organo-modified SWCNT monolayer itself shows a fibrous aggregated morphology. [25,26] On the other hand, it can be confirmed that finely shaped deposits are present on the overall surface of each inorganic fiber in the organo-modified SWCNT monolayer in which protease was allowed to act from the subphase. This morphological feature is distinct from that of the organo-modified SWCNT monolayer.…”

“…So far, studies have been conducted on SWCNT Langmuir monolayers modified by long-chain fatty acids [25] and non-desorbable longchain phosphonic acids. [26] Organo-modified SWCNTs can be dispersed not only in organic solvents but also in organic polymers, [27] and orientation control using this technique [28] has been studied. Biomolecule adsorption/immobilization technology, [29] which utilizes the air/water interface, has the potential to control adsorption density by adjusting surface pressure.…”

Nanofiller dispersing, drawn orientation, and mechanical properties of polymer‐based composites via organo‐modification of single‐walled carbon nanotubes obtained by two‐types of manufacturing processes

“…Figure 3 shows the morphological evaluation of FDP-iA SWCNTs and FDP-sg SWCNTs by AFM. Monolayers of these two materials were formed using the Langmuir-Blodgett method [48][49][50] so that they could be compared more precisely. Both types of SWCNTs formed fibrous aggregate morphologies.…”

“…In this study, fluorocarbon‐modified SWCNTs were prepared, [ 48 ] and the effect of increased dispersibility by the addition of a small amount of a simple substance as a dispersant aid on the structural properties of fluoropolymer‐based composites containing two types of SWCNTs was studied. As mentioned above, two types of SWCNTs with different manufacturing methods have been compared as interfacial films, but there are no examples of comparison as fillers for polymer‐based composites.…”