10.1021/acs.jpcc.7b03645.s005 Cailong Zhou Cailong Zhou Huijing Li Huijing Li Jing Lin Jing Lin Kun Hou Kun Hou Zhijie Yang Zhijie Yang Pihui Pi Pihui Pi Shouping Xu Shouping Xu Xiufang Wen Xiufang Wen Jiang Cheng Jiang Cheng Matchstick-Like Cu<sub>2</sub>S@Cu<sub><i>x</i></sub>O Nanowire Film: Transition of Superhydrophilicity to Superhydrophobicity American Chemical Society 2017 mixture surface morphology matchstick-like structures superhydrophilic copper mesh contact angle measurement Scanning Electron Microscopy SEM surface chemical composition XRD XPS nanowire chemical composition superhydrophobic Cu X-ray Photoelectron Microscopy wettability transition 2017-08-22 00:00:00 Media https://acs.figshare.com/articles/media/Matchstick-Like_Cu_sub_2_sub_S_Cu_sub_i_x_i_sub_O_Nanowire_Film_Transition_of_Superhydrophilicity_to_Superhydrophobicity/5363683 We fabricated a matchstick-like Cu<sub>2</sub>S@Cu<sub><i>x</i></sub>O nanowire film on copper mesh by applying a Cu­(OH)<sub>2</sub> nanowires template-sacrificial method, which can transformed from superhydrophilic to superhydrophobic just after storage in air for a certain period without any further organic modification. The surface morphology, chemical composition and the wettability were investigated by Scanning Electron Microscopy (SEM), X-ray diffractometer (XRD), Raman, X-ray Photoelectron Microscopy (XPS), and contact angle measurement. Results showed that the change of surface chemical composition and the trapped air among the matchstick-like structures were the decisive factors for the wettability transition. Therefore, on-demand oil/water separation was achieved, which was performed by using the superhydrophilic–underwater superoleophobic mesh for separating light oil/water mixtures and the superhydrophobic one for separating heavy oil/water mixtures.