Oca25 contact angle meter

The morphologies and microstructures of all electrodes were characterized by scanning electron microscopy (SEM, MIRA3) equipped with an energy dispersive X-ray spectroscopy (EDS, Aztec Energy), transmission electron microscopy (TEM, FEI tecnai G2 F20), and electron probe micro-analyzer (EPMA-1610, SHIMADZU). Phase compositions of the as-prepared samples were investigated by X-ray diffraction (XRD, Rigaku MiniFlex 600). The valence information of elements in all samples was tested by X-ray photoelectron spectroscopy (XPS ESCALAB 250Xi). The contact angle between electrodes and water was measured on a Dataphysics OCA25 contact angle meter. The interfacial adhesion of the electrolytic film on the surface of the electrode was measured by a WS-2005 scratch tester. The hydrogen evolution process of each electrode was recorded with a SONY FDR-AXP55 camera.

The WCAs of the zein nanofiber samples on the glass slide were measured using an OCA 25 contact angle meter (DataPhysics Instruments GmbH, Filderstadt, Germany). Briefly, 3 μL of distilled water was pipetted onto the samples, and the WCA was recorded at t = 5 s after the waterdrop had made contact with the nanofiber samples. Five tests were performed for each nanofiber sample.