Sensitivity Enhancement of Benzene Sensor Using Ethyl Cellulose-Coated Surface-Functionalized Carbon Nanotubes

Abstract

A hybrid sensor based on the integration of functionalized multiwalled carbon nanotubes (MWCNTs) with ethyl cellulose (EC) was fabricated for sensitivity enhancement of benzene detection. To functionalize the surface of MWCNTs, MWCNTs were treated with hydrochloric acid for 60 min (A60-MWCNTs), while other MWCNTs were treated with oxygen plasma for 30, 60, 90, and 120 min (P30-MWCNTs, P60-MWCNTs, P90-MWCNTs, and P120-MWCNTs, resp.). Pristine MWCNTs, A-MWCNTs, and P-MWCNTs were dispersed in 1,2-dichloroethane, then dropped onto a printed circuit board consisting of Cu/Au electrodes used as the sensor platform. Next, EC was separately spin coated on the pristine MWCNTs, A-MWCNTs, and P-MWCNTs (EC/MWCNTs, EC/A-MWCNTs, and EC/P-MWCNTs, resp.). All sensors responded to benzene vapor at room temperature by increasing their electrical resistance which was sensitive to benzene vapor. The EC/P90-MWCNTs enabled an approximately 11-fold improvement in benzene detection compared to EC/MWCNTs. The sensitivity of all sensors would be attributed to the swelling of EC, resulting in the loosening of the MWCNT network after benzene vapor exposure. The differences of the sensing responses of the EC/MWCNTs, EC/A-MWCNTs, and EC/P-MWCNTs would be ascribed to the differences in crystallinity and functionalization of MWCNT sidewalls, suggesting that acid and oxygen plasma treatments of MWCNTs would be promising techniques for the improvement of benzene detection.

Synthesis and Characterization of Zinc Oxide-Reduced Graphene Oxide Hybrid Materials and their Application for Nitrogen Dioxide Detection

“…The Raman spectra of rGO and ZnO-rGO consist of two characteristic peaks which are the D-and G-bands at ~1330 and ~1598 cm -1 , respectively (data not shown). The G-band indicates the signal reflection a graphitic structure that is emitted from the stretching vibration of the sp 2 carbon while the D-band corresponds to a disordered carbon structure and the sp 3 hybridized carbon [12][13]. The results showed that the rGO maintained their structure after coating with ZnO.…”

Carbon Nanostructures as a Multi-Functional Platform for Sensing Applications

“…Most investigations have focused on detecting oxygen (O2) [9,10], ozone (O3) [11], carbon monoxide (CO) [12,13], carbon dioxide (CO2) [14], ammonia (N3) [15], sulfur dioxide (SO2) [15] and hydrogen (H2) [16,17]. Other organic gases such as ethanol [18], benzene [19], isopropanol [20], acetone [21,22] and methanol [23] have also called attention to be detected. Different biological electroactive species and other biomolecules as glucose [24,25], neurotransmitters [26], ascorbic acid [27,28], uric acid [29], hydrogen peroxide (H2O2) [30] among others are also of great interest to be monitored due to the need of diagnosis of diseases [31].…”