Starch-Mediated Immobilization, Photochemical Reduction, and Gas Sensitivity of Graphene Oxide Films

Priscilla P Peregrino; Marco R Cavallari; Fernando J Fonseca; Sanclayton G C Moreira; Maria José A Sales; Leonardo G Paterno

doi:10.1021/acsomega.9b03892

Starch-Mediated Immobilization, Photochemical Reduction, and Gas Sensitivity of Graphene Oxide Films

ACS Omega. 2020 Mar 5;5(10):5001-5012. doi: 10.1021/acsomega.9b03892. eCollection 2020 Mar 17.

Authors

Priscilla P Peregrino¹, Marco R Cavallari^{2

3}, Fernando J Fonseca³, Sanclayton G C Moreira⁴, Maria José A Sales¹, Leonardo G Paterno¹

Affiliations

¹ Laboratório de Pesquisa em Polímeros e Nanomateriais, Instituto de Química, Universidade de Brasília, Brasília, DF 70904-970, Brazil.
² Universidade Federal da Integração Latino-Americana, Engenharia de Energia, Foz do Iguaçú, PR 85866-000, Brazil.
³ Departamento de Engenharia de Sistemas Eletrônicos, Escola Politécnica da Universidade de São Paulo, São Paulo, SP 05424-970, Brazil.
⁴ Instituto de Ciências Exatas e Naturais (ICEN), Universidade Federal do Pará, Belém, PA 66075-900, Brazil.

Abstract

This work unveils the roles played by potato starch (ST) in the immobilization, photochemical reduction, and gas sensitivity of graphene oxide (GO) films. The ST/GO films are assembled layer by layer (LbL) onto quartz substrates by establishing mutual hydrogen bonds that drive a stepwise film growth, with equal amounts of materials being adsorbed in each deposition cycle. Afterward, the films are photochemically reduced with UV irradiation (254 nm), following a first-order kinetics that proceeds much faster when GO is assembled along with ST instead of a nonoxygenated polyelectrolyte, namely, poly(diallyl dimethylammonium) hydrochloride (PDAC). Finally, the gas-sensing performance of ST/reduced graphene oxide (RGO) and PDAC/RGO sensors fabricated via LbL atop of gold interdigitated microelectrodes is evaluated at different relative humidity levels and in different concentrations of ammonia, ethanol, and acetone. In comparison to the PDAC/RGO sensor, the ones containing ST are much more sensitive, especially when operating in a high-relative-humidity environment. An array comprising these chemical sensors provides unique electrical fingerprints for each of the investigated analytes and is capable of discriminating and quantifying them in a wide range of concentrations, from 10 to 1000 ppm.