Deep understanding of the dependence between Cu surface wettability and C-adsorption/desorption

Abstract

The dependence between the surface wettability of hydrothermally-treated Cu and C-adsorption/desorption is unclear, which restricts further expanding the practical applications of the superhydrophobic surfaces obtained via hydrocarbon adsorption and developing promising reversible super-wettability transition methods. Herein, spectroscopic (Raman and XPS) and microscopic (FESEM, AFM, SKPM) characterization results reveal that the superhydrophobicity of the hydrothermal Cu foil surfaces with micro-scaled Cu oxides depends on the adsorption of volatile C-containing organic species and is independent of the types of Cu oxides. Theoretical calculation results manifest that the adsorptions of volatile C-containing organic species on Cu2O and CuO both belong to strong chemisorptions. Inspired by the as-established dependence between Cu surface wettability and adsorption/desorption of volatile C-containing organic species, we develop facile, cost-effective, and environmental-friendly methods for reversibly modulating Cu surface super-wettability, which are accomplished by storing the sample with micro-structured Cu oxide(s) in C-rich ambience to realize superhydrophobicity and heating the superhydrophobic sample via short-time IR irradiation to achieve superhydrophilicity. Moreover, these super-wettability reversible transition methods are proved to be effective for other materials.