Author, as appears in the article.: Casanova-Chafer, Juan Bittencourt, Carla Llobet, Eduard

Department: Enginyeria Electrònica, Elèctrica i Automàtica

URV's Author/s: Llobet Valero, Eduard

Keywords: Vapor Thiol Sensitivity Self-assembled monolayer (sam) Percolation Nitrogen-dioxide Networks Multiwall carbon nanotubes (mwcnts) Hydrophobicity Hydrophilicity Gas sensing mechanism Films Carbon length chain Au self-assembled monolayer (sam) multiwall carbon nanotubes (mwcnts) hydrophobicity hydrophilicity gas sensing mechanism carbon length chain

Abstract: © 2019 Casanova-Cháfer et al. Here we describe the development of chemoresistive sensors employing oxygen-plasma-treated, Au-decorated multiwall carbon nanotubes (MWCNTs) functionalized with self-assembled monolayers (SAMs) of thiols. For the first time, the effects of the length of the carbon chain and its hydrophilicity on the gas sensing properties of SAMs formed on carbon nanotubes are studied, and additionally, the gas sensing mechanisms are discussed. Four thiols differing in the length of the carbon chain and in the hydrophobic or hydrophilic nature of the head functional group are studied. Transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy are used to analyze the resulting gas-sensitive hybrid films. Among the different nanomaterials tested, short-chain thiols having a hydrophilic head group, self-assembled onto Au-decorated carbon nanotubes were most responsive to nitrogen dioxide and ethanol vapors, even in the presence of ambient humidity. In particular, this nanomaterial was about eight times more sensitive to nitrogen dioxide than bare Au-decorated carbon nanotubes when operated at room temperature. This response enhancement is attributed to the interaction, via strong hydrogen bonding, of the polar molecules tested to the polar surface of hydrophilic thiols. The approach discussed here could be extended further by combining hydrophilic and hydrophobic thiol SAMs in Au-MWCNT sensor arrays as a helpful strategy for tuning sensor response and selectivity. This would make the detection of polar and nonpolar gas species employing low-power gas sensors easier, even under fluctuating ambient moisture conditions.

Thematic Areas: Química Physics, applied Physics and astronomy (miscellaneous) Physics and astronomy (all) Nanoscience and nanotechnology Nanoscience & nanotechnology Materials science, multidisciplinary Materials science (miscellaneous) Materials science (all) Interdisciplinar General physics and astronomy General materials science Engenharias iv Engenharias iii Electrical and electronic engineering Astronomia / física

licence for use: https://creativecommons.org/licenses/by/3.0/es/

ISSN: 21904286

Author's mail: eduard.llobet@urv.cat

Author identifier: 0000-0001-6164-4342

Record's date: 2023-02-18

Papper version: info:eu-repo/semantics/publishedVersion

Link to the original source: https://www.beilstein-journals.org/bjnano/articles/10/58

Licence document URL: http://repositori.urv.cat/ca/proteccio-de-dades/

Papper original source: Beilstein Journal Of Nanotechnology. 10 565-577

APA: Casanova-Chafer, Juan Bittencourt, Carla Llobet, Eduard (2019). Hydrophilicity and carbon chain length effects on the gas sensing properties of chemoresistive, self-assembled monolayer carbon nanotube sensors. Beilstein Journal Of Nanotechnology, 10(), 565-577. DOI: 10.3762/bjnano.10.58

Article's DOI: 10.3762/bjnano.10.58

Entity: Universitat Rovira i Virgili

Journal publication year: 2019

Publication Type: Journal Publications