(Nafion-membrane-Nafion) was determined at the frequency, where the phase angle amongst
(Nafion-membrane-Nafion) was determined at the frequency, exactly where the phase angle among current and voltage was 0 . Following measurement in the three-membrane stack, Rohmic of the two Nafion membranes was measured. The difference Rohmic (Nafionmembrane-Nafion) ohmic (Nafion-Nafion) yielded the preferred impedance in the tested membranes. The second EIS device was only applied for those membranes which have already been also tested in situ in the electrolyzer. These measurements have been carried out in a Membrane Test Technique (MTS740) from Scribner Associates Inc, USA. A detailed description and also the technical data for the setup are given elsewhere [46]. For the sample preparation, the membrane sample inside a size of 3 cm 1 cm was compressed among two gas diffusion layers (GDLs) (SIGRACETGDL 25BC, Ion energy GmbH) and attached to the platinum electrodes with conductive carbon paint. The sample compression in between the electrodes was 200 PSI (or 1.38 MPa). Electrochemical impedance spectroscopy (EIS) (Impedance Analyzer 1260, Solartron Analytical) was recorded following every temperature step. The temperature of measurement was varied from 30 to 110 C, at a continual relative humidity of 90 . two.3.4. Thermal Stability via Thermogravimetry Coupled with a Fourier ransform Infrared Spectrometer (TGA TIR) The thermal stability on the synthesized polymers and membranes was determined through thermogravimetric evaluation (TGA). The samples were heated in the TGA cell of a Netzsch STA 449C or STA 449 F3 Jupiter in an oxygen-rich atmosphere (605 O2 , 405 N2 ) in an aluminum oxide crucible at a constant heating rate (20 K/min) to a previously defined maximum temperature Tmax (600 C). This instrument was coupled via a heated transfer line to an FT-IR spectrometer (Nicolet 6700 Thermofisher or Bruker Perseus FT-IR), with which the series of FTIR spectra of decomposition gases was measured. Just about every FTIR spectrum may very well be assigned to a particular temperature at which it was recorded. TSO3H-onset was identified by way of the asymmetrical stretching vibration of your S=O bond (1352342 cm-1 ), indicating the onset of SO3 H group splitting-off, and TCO-onset by means of the valence vibration from the C=O bond (2144 cm-1 ), indicating the onset of backbone degradation [47]. 2.3.five. Size Exclusion Chromatography (SEC) Size exclusion chromatography (SEC) or gel permeation chromatography (GPC) enables the determination of your molecular weight distribution (MWD, Mn, and Mw ) of a polymer by its fractionation primarily based on hydrodynamic volume on the macromolecular chains of the respective chain lengths. The MWD makes it possible for averaging for Mn and Mw with Mn Mw . The width of an MWD is known as polydispersity (PD) and is calculated from the quotient Mw /Mn . Calibration was performed with MAC-VC-PABC-ST7612AA1 medchemexpress polystyrene typical (PSS ReadyCal Kit). N,N-dimethylacetamide (DMAc), to which 5.0 g per L lithium bromide (LiBr) was added, which was employed as the mobile phase (eluent). The samples were measured applying an Agilent Technologies 1200 Series GPC technique. A differential refractometer (Shodex RI 71), a Combretastatin A-1 Epigenetic Reader Domain viscometer (PSS ETA-2010), as well as a multi-angle light scattering (MALLS) photometer (PSS SLD 7000) served as detectors. The stationary phase consisted of separation columns from Polymer Requirements Service GmbH (PSS), namely a column mixture of various pore sizes (PSS PFG, five , 300 PSS PFG 5 , 1000 . two.3.6. Stress train Measurements of Selected Membranes Mechanical properties of your membranes were measured at room temperature by utilizing an EZTest Comp.