Lext ols5000

The top surface of TFNC membranes was examined using CLSM (Olympus LEXT OLS5000, Tokyo, Japan) to visualize 2D and 3D morphologies with a scanned area of 644 µm × 648 µm. The lateral scanning detection was performed by locating the area with an edge boundary between each region of nanofiber support and PA thin film with optical images captured at 20× and 50× magnification. The image profile was generated by the Olympus OLS5100 data acquisition application.

The surface roughness of the coatings was studied using a confocal laser scanning microscope (Olympus LEXT OLS5000, Olympus Corporation, Tokyo, Japan) with a MPLFLN5× (numerical aperture 0.15, working distance 20 mm), MPLFLN10xLEXT (numerical aperture 0.3, working distance 10.4 mm), and LMPLFN20xLEXT (numerical aperture 0.45, working distance 6.5 mm) objectives. The microscope is equipped with a 405 nm violet laser, which enables a lateral resolution of down to 0.12 µm. The 2D CSLM micrographs of the fracture surfaces between wood and the coatings were used for the determination of the thickness of the various coatings; the values were average of at least 10 measurements performed on various samples and at different locations. The surfaces of the coatings and their interfaces with the wood were also analyzed by SEM-EDX. The micrographs were taken at a 20 kV voltage and a pressure of 50 Pa using a large field (LFD) detector in a Quanta 250 scanning electron microscope (FEI Company, Hillsboro, OR, USA) at working distances between 7 and 11 mm at magnification 150× and 300×. The analyzed interfaces were fracture surfaces obtained by splitting the coated wood samples in the longitudinal direction.

The graphite coating is prepared by spray coating graphite (Cramolin, ITW Spraytec, Germany) onto a precleaned silicon wafer (r = 2.5 cm), followed by evaporation of the solvent at ambient temperature.
The layer thickness of the reference samples, namely PDMS films and graphite, was determined by using a three-dimensional (3D) laser scanning microscope (LEXT OLS5000, Olympus). A thickness of 88.4 μm, 13.1 μm, 8.6 μm, 712 nm, and 3.2 μm was obtained for the four PDMS films and the graphite coating, respectively.

The films were obtained by using a Lenpipet Light dispenser (Thermo Fisher Scientific, Walthem, MA, USA) with a working volume of 1–10 μL. The volume of the initial drops during application and the drying time were 8 μL and 45 min, respectively. As a result, the average thickness of the films based on MEGl and EGl were 4.7 µm and 1.5 µm, respectively. The film area in both cases was 35 mm². The images of the films based on MEGl and EGl obtained by means of a laser confocal microscope Lext OLS5000 (Olympus, Tokyo, Japan) at a laser scanning mode and their 3D visualization created by using the built-in software are shown in Figure 3. It can be seen that the MEGl film has a higher roughness than the EGl one. The higher roughness of the MEGl film, as well as its large thickness, is associated with the presence of fungal mycelium particles. It is possible to see that the MEGl film is more heterogeneous and rough than the EGl one.

Images of the internal microstructure were obtained with a LEXT OLS5000 laser-scanning confocal microscope (Olympus Corp., Tokyo, Japan). Examples are shown in Figure 3c. The total length of a single microstructural channel (l) was 1.8 mm. The length of each main cone was 1.5 mm, the length of the second cone was 0.3 mm, and the height of the microstructure was 0.8 mm. The inclination of the main cone (α) was 10°, while that of the second cone (β) was 41°.