Auriga crossbeam

For characterisation of the morphology of PCL and PCL-PEG scaffolds SEM (Auriga CrossBeam, Carl Zeiss Microscopy GmbH, Oberkochen, Germany) was used.

Electrodes were mechanically characterized via the scotch tape test in order to test whether they were sufficiently adhered to the glass substrate. Additionally, electrodes were characterized by cyclic voltammetry. A commercial portable potentiostat (Emstat 3, Palmsens) controlled by PSTrace software was employed for all voltammetric studies. The planar electrodes were also imaged by scanning electron microscopy; standard imaging was performed on a JEOL JSM 6010 LA (JEOL, Japan) and high-resolution imaging on a Zeiss Auriga Cross Beam. SEM images were obtained using 3 separate electrode devices to ensure reproducibility. Samples were mounted onto metal stubs with double sided carbon tape and gold-coated with an automated sputter coater (Emtech K575X, Quorum Technologies) for 10 min prior to imaging.

The surface topography of the casted materials (with and without 5CB) was observed by Scanning Electron Microscopy (SEM). SEM images were obtained on a Zeiss Auriga CrossBeam workstation equipped with a focused ion beam (FIB) column. The materials were previously coated with 20 μm of AuPd for better conductivity and placed on a carbon-aluminium support. Polarized Optical Microscopy (POM) was used to investigate the distribution of 5CB on the suberin matrix. POM images were taken with crossed (at 90°) polarizers and complemented with bright field (BF) microscopy images, using a Zeiss Axio Observer. Z1/7 microscope equipped with an Axiocam 503 colour camera and operated with ZEN 2.3 software for acquisition and processing of the images. The films surface composition was characterized by X-ray photoelectron spectroscopy (XPS). XPS was performed with a Kratos AXIS Supra spectrometer using a monochromated Al Kα source, running at 225 W. The detailed spectra were recorded with a pass energy of 5 eV. Charge neutralization with an electron flood gun was employed during the measurements, and all spectra were charge corrected to the C–C, C–H of the C 1s emission at 285 eV.

SEM with a field emission gun (Schottky‐type) was performed to investigate the surface of the electrodes and the particle size and architecture. The measurements were carried out on multiple areas of the sample using an Auriga CrossBeam workstation from Zeiss (Germany). Cross‐sections were prepared by means of FIB milling using gallium ions generated from a liquid metal ion source. EDX was conducted to examine the elemental composition of the surface and cross‐section on multiple areas of the sample. The measurements were performed with an accelerating voltage of 15 kV using an Ultim® Extreme EDX detector and evaluated with the INCA software, both from Oxford Instruments (United Kingdom). ToF‐SIMS was performed using a TOF.SIMS 5 instrument from ION TOF GmbH (Germany). The nanoscale elemental mapping of the cross‐section was carried out with a liquid metal bismuth ion source (Bi⁺ 30 keV) in the imaging mode combined with delayed secondary ion extraction. The positive electrodes were analyzed by SEM, EDX, and ToF‐SIMS after washing with 1 mL EMC.

The average size of graphite was calculated using selected 20 graphite particles from the scanning electron microscopy (SEM) image in Figure S3. The size (length/height/thickness) was measured and averaged by using the ImageJ software. Raman spectroscopy was performed on a Renishaw Raman instrument using a 532 nm laser. The morphology and shape of samples were obtained using SEM, Zeiss Auriga Cross Beam. X‐ray diffraction (XRD) measurement was carried out by an X'Pert PRO PANalytical (40 mA and 40 kV for power settings). The Brunauer–Emmett–Teller (BET) method and density functional theory (DFT) were used to evaluate the surface area and pore size distribution from the N₂ adsorption/desorption isotherm by a physisorption instrument (Micromeritics 3 Flex).

Scanning electron microscopy (SEM) observations were conducted on a Carl Zeiss AURIGA CrossBeam (FIB-SEM) workstation coupled with energy dispersive X-ray spectroscopy (EDS, Oxford X-Max 150 detector with Aztec software). It was also used TM3030Plus tabletop Microscope from Hitachi. The fibers were previously coated with an Pd conductive film to avoid charge effects.