Auriga laser

The inner and surface morphology of dense and porous PVDF and PVDF/nanoparticle membranes were studied by scanning electron microscopy (SEM) using the scanning electron microscope Zeiss AURIGA Laser (Carl Zeiss SMT, Oberhochen, Germany) at 1 kV. The cross sections of dense and porous membranes were obtained by cooling the membranes in liquid nitrogen, followed by fracturing perpendicular to the surface.

Cross-sectional scanning electron microscopic (SEM) images of the multilayer structure were obtained by ZEISS Auriga Laser (Carl Zeiss, Oberkochen, Germany) combined with a focused ion beam (FIB) with a Ga⁺ ion source. The FIB processing was performed for the carbon protection coating (deposited from carbon gas) and subsequent making of crevices to reveal the cross-sectional observation surface. Next, the microstructure was observed by SEM operated at 1 kV under a 54° gradient condition. Cross-sectional high-angle annular dark field scanning TEM (HAADF-STEM) images were obtained by Tecnai Osiris (FEI, Hillsboro, OR, USA). Before FIB processing with a Ga⁺ ion source (FB-2100, Hitachi, Tokyo, Japan), the substrates were coated with a chromium (Cr)-containing oil-based ink to protect the surface. Next, FIB processing was performed for the tungsten (W) protection coating (deposited from W(CO)₆ gas) and subsequent preparation of the cross-sectional samples. Each sample was then mounted on a copper (Cu) FIB lift-out grid and thinned to approximately 100 nm. The prepared cross-sectional ultrathin samples were analyzed using HAADF-STEM operated at 200 kV.

Surface morphologies and topographies were analyzed by scanning electron (SEM) and atomic force microscopy (AFM) using Zeiss AURIGA Laser (Oberkochen, Germany) and INTEGRA-Aura Spectrum Instruments (Moscow, Russia), respectively. Before the registration of SEM images, the surfaces of film specimens were additionally deposited with conductive carbon layers. The AFM images were analyzed with the WSxM software (version 4.0, Julio Gómez Herrero & José María Gómez Rodríguez, Madrid, Spain) [35 (link)]. Polarized light microscopy was carried out by means of a Leica DM4500 P instrument (Leica Microsystems, Wetzlar, Germany) in transmittance mode. The Rigaku MiniFlex II system (Tokyo, Japan) was applied for the analysis of crystallinity of pure and composite film specimens.