An Al-assisted GO/rGO Janus film: Fabrication and hygroscopic properties. (January 2021)

• Record Type: Journal Article
• Authors: Lee, Seul-Yi; Moore, Robert B.; Mahajan, Roop L.
• Is Part Of: Carbon. Volume 171(2021)
• Page Start: 585
• Page End: 596
• Publication Date: 2021-01
• Subjects: Janus films -- Graphene oxide/reduced graphene oxide films -- Nascent hydrogens -- Hygroscopic properties -- Humidity sensors -- Actuators; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2020.09.002
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: In this paper, we present a novel method combining drop-casting GO dispersion with an Al-assisted partial reduction technique to fabricate a freestanding Janus GO/rGO film. The laminar structure of Janus film facilitates the diffusion pathway of water molecules efficiently. The asymmetrical oxygen content of the film promotes a significant gradient of moisture uptake in GO (hydrophilic) and rGO (hydrophobic) layers, resulting in a macroscopic deformation of the Janus film proportional to the change in relative humidity. The induced strain in the film changes the resistance of the rGO film, which systematically varies as a function of the strain amplitude or equivalently the change in relative humidity. In the range of relative humidity (5 to 100%), the resistance increases gradually with measurable change in response to a change in relative humidity (RH) as low as 1%, with the change being steeper at RH >85%. The results provide foundational knowledge for developing a relative humidity sensor with high sensitivity, excellent repeatability, and fast response-recovery without the complexity of the currently available interdigitated transducer-based humidity sensors. Graphical abstract: Image 1