A Facile and Efficient Protocol for Preparing Residual-Free Single-Walled Carbon Nanotube Films for Stable Sensing Applications

Abstract

In this article, we report on an efficient post-treatment protocol for the manufacturing of pristine single-walled carbon nanotube (SWCNT) films. To produce an ink for the deposition, the SWCNTs are dispersed in an aqueous solution with the aid of a carboxymethyl cellulose (CMC) derivative as the dispersing agent. On the basis of this SWCNT-ink, ultra-thin and uniform films are then fabricated by spray-deposition using a commercial and fully automated robot. By means of X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), we show that the CMC matrix covering the CNTs can be fully removed by an immersion treatment in HNO3 followed by thermal annealing at a moderate temperature of 100 °C, in the ambient air. We propose that the presented protocols for the ink preparation and the post-deposition treatments can in future serve as a facile and efficient platform for the fabrication of high-quality and residual-free SWCNT films. The purity of SWCNT films is of particular importance for sensing applications, where residual-induced doping and dedoping processes distort the contributions from the sensing specimen. To study the usability of the presented films for practical applications, gas sensors are fabricated and characterized with the CNT-films as the sensing material, screen printed silver-based films for the interdigitated electrode (IDE) structure, and polyimide as a flexible and robust substrate. The sensors show a high and stable response of 11% to an ammonia (NH3) test gas, at a concentration of 10 ppm.

Colorimetric strategy for ascorbic acid detection based on the oxidase‐like activity of silver nanoparticle single‐walled carbon nanotube composites

“…[ 19 ] C=O and C–O bonds are mainly present in oxidized CNTs. [ 20 ] These findings suggested that the SWCNTs possessed enough carboxyl groups to provide accessible conjugated sites for formation of composites. The typical XPS spectrum (Figure 1f) for Ag 3 d had two peaks centred at 373.7 and 367.7 eV, and associated with Ag 3 d 3/2 and Ag 3 d 5/2 .…”

Cost-Effective PEDOT:PSS Temperature Sensors Inkjetted on a Bendable Substrate by a Consumer Printer

“…The excitation voltage applied in all measurements was V DC = 0 and V AC = 500 mV in the frequency range from 100 Hz to 10 MHz. Calibration was done to compensate for the parasitic elements in agreement with previous work [36,37]. The sensor was placed in a climatic chamber VLC4006) from Vötsch Industrietechnik GmbH (Balingen, Baden-Wuerttemberg, Germany) with temperature and humidity control.…”

Colloidal and rheological characterization of SWCNT in biological media

“…SWCNT suspensions were characterized by measuring the zeta potential as a function of pH using the microelectrophoresis technique assisted with laser Doppler velocimetry (Zetasizer NanoZS, Malvern, United Kingdom). The zeta potential of suspensions was determined at 25.0 ± 0.1°C, for pH values between 4 and 9, broader than the physiological pH range (6)(7)(8).…”

“…According to the number of graphene layers, CNTs are conventionally classified as Single-Walled-(SWCNT) or Multi-Walled-(MWCNTs) Carbon Nanotubes. Since their discovery, numerous studies have developed very creative CNTs applications, including multifaceted sensors, and those in nanotechnology, material science, electronics, optics, gas storage and biomedicine [2][3][4][5][6][7].…”