Axis supra surface analysis instrument

Unless specified otherwise, coated membranes were used before re-swelling as described in 2.2 and 2.3, uncoated membranes were treated with NaOH as described in 2.2 and 2.3, respectively, and used after drying under vacuum for 1 h at 60 °C.
Membranes were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR) and contact angle measurements. SEM pictures of dry membranes were collected on a Zeiss Leo 1530 VP (Jena, Germany) to analyze the surface morphology. IR spectra were collected on a Vertex 70 spectrometer (Bruker, Germany) (spectra see supporting information). Water-air contact angles of membranes re-swollen in ultrapure water were measured using the captive bubble method with an OCA40 (Dataphysics, Germany). XPS spectra were measured on an AXIS Supra surface analysis instrument (Kratos Analytical, England).

Raman spectroscopy (inVia™ confocal Raman microscope) was performed with a 532 nm laser source to evaluate the graphitic microstructure of pyrolytic carbons. X-ray photoelectron spectroscopy (Kratos AXIS-SUPRA surface analysis instrument) was used to assess the percentage of nitrogen and oxygen groups in the carbon nanofibers. The mechanical characterization was performed by Dynamic Mechanical Analysis (DMA) using a Q800 DMA (TA Instrument, Inc, New Castle, DE, USA) with tensile film clamp. The mats were cut into rectangular ribbons with dimensions recorded. Then, the standard stress and strain tests were obtained with a controlled force ramping rate at 1 N/min until the samples yielded from center.