Leo gemini 1550 vp

Scanning electron microscopy (SEM) of the membranes was carried out on a LEO Gemini 1550 VP (Zeiss, Oberkochen, Germany) at a voltage of 3 or 5 kV. The samples were coated with 2.0 nm platinum using a coating device Bal-tec MED 020 (Bal-tec/Leica Microsystems GmbH, Wetzlar, Germany). Cross-sections of the membranes were prepared while dipping the membranes in isopropanol, freezing in liquid nitrogen, and breaking. Average pore size values were determined using the software Analysis (Olympus Soft Imaging Solutions GmbH, Münster, Germany) based on the SEM results.

To obtain information about the membrane morphology, scanning electron microscopy (SEM) investigations were carried out on either a LEO Gemini 1550 VP or a Merlin (both from Zeiss, Oberkochen, Germany) at an acceleration voltage of 1–5 kV, respectively. Cross-sections were prepared under cryogenic conditions. All samples were sputtered with ca. 2 nm of platinum as a conductive layer. Secondary electron In-Lens and HE-SE2 detectors were used for imaging the membrane morphology and topography. To obtain the average pore diameter, the SEM micrographs were analyzed by IMS V15Q4 (Imagic Bildverarbeitung AG, Glattbrugg, Switzerland), more details are given in ESI.

Scanning electron microscope studies on the membranes were carried out with a LEO Gemini 1550 VP (Zeiss) with field emission cathode operated at 1–1.5 kV. The membrane sample preparation for cross-section analysis was done under cryogenic conditions and samples were sputtered by a very thin layer of Au/Pd.