Dimension icon system

Multiple microscopy techniques were used to assess the surface morphology and thickness of BPNSs. Atomic force microscopy (AFM) was employed to perform a vacuum-based characterization of the surface morphology and thickness of the BPNSs at room temperature, utilizing the Dimension Icon system (Bruker, Karlsruhe, Germany). Meanwhile, scanning electron microscopy (SEM) was used to examine the surface morphology of the BPNSs by depositing them onto an aluminum foil and drying at 60 °C prior to imaging. The imaging was carried out under high vacuum with an acceleration voltage of 10 kV using the Sigma 300 system (Zeiss, Oberkochen, Germany). Lastly, transmission electron microscopy (TEM) was employed to determine the elemental compositions and morphologies of the BPNSs utilizing the FEI Tecnai F20 TEM D545 system (FEI, Hillsboro, OR, USA). The Raman spectra of the BPNSs were obtained at room temperature using Raman spectroscopy (LabRAM HR, HORIBA, Montpellier, France) with an excitation wavelength of 532 nm. The particle size distribution and polydispersity (PDI) in water were determined using a Zetasizer 3000 HS nanosizer (Malvern Instruments, Malvern, UK).

The morphology of the samples was examined using optical microscopy (OM, Carl Zeiss Microscopy GmbH, Jena, Germany) and scanning electron microscopy (SEM, Nova Nano SEM 200 FEI, Hillsboro, OR, USA). Their chemical compositions were assessed through Raman and photoluminescence (PL) spectra at room temperature. Raman spectra were obtained using a micro confocal Raman/PL spectrometer (Renishaw in Via, Gloucestershire, UK) with an excitation laser line operating at 532 nm. Flake thickness measurements were conducted using atomic force microscopy (AFM) with a Dimension Icon system from Bruker, San Diego, CA, USA. The crystallinity quality and chemical composition of the Sb₂Te₃ and Sb₂Te₃/WS₂ flakes were investigated using transmission electron microscopy (TEM, JEOL 2100F, Tokyo, Japan) and X-ray photoelectron spectroscopy (XPS) analysis performed on a PHI 5000 VP III instrument, Woodbury, MN, USA.

The Dimension Icon system from Bruker operating
in the PeakForce quantitative nanoscale mechanical (QNM) mode was
used for atomic force microscopy (AFM) measurements. The probe used
was a ScanAsyst Air tip with a spring constant of 0.4 N m^–1, and a tip–sample contact force of 5.0 nN was used for all
measurements.

AFM analyses of the COPET-PLLA blends were performed on trimmed surfaces with a Dimension Icon system (Bruker Corp., Billerica, MA, USA) in PeakForce Tapping mode with Quantitative Nanomechanical Mapping (PFT-QNM). A factory-calibrated probe, RTESPA-300–30 (Bruker Corp., Billerica, MA, USA), with a spring constant of 48.87 N m⁻¹ and a tip apex radius of 34 nm was used. AFM images (256 × 256 pixels) with dimensions ranging between 3 × 3 and 30 × 30 µm² were acquired. The PeakForce frequency and amplitude were 2 kHz and 30 nm, respectively. The PeakForce set point was set to 75 nN, corresponding to an indentation depth between 2 and 3 nm. Under these conditions, the contact radius remained smaller than 10 nm [25 (link)].

The obtained structures were characterized by AFM, performed on a Dimension Icon system (Bruker, Berlin, Germany) in tapping mode. Tap300-G probes (Budget Sensors, Sofia, Bulgaria) with a resonance frequency of 330 kHz and nominal spring constant of 42 N/m were used. The indentation maps from which Young’s modulus values were extracted were obtained on a JPK BioAFM system (Bruker, Berlin, Germany), using BL-AC40TS probes with a radius of 8 nm (Asylum Research, Santa Barbara, CA, USA), with a resonance frequency of 70 Hz and nominal force constant of 2 N/m. A total of 625 force curves were analysed from areas of 2.5 × 2.5 µm², with the printed feature located at the centre of the scanning area. The data obtained from the measurements were processed by fitting the force curves to the Hertz model, by selecting tip shape as pyramidical and Poisson’s ratio of 0.5. The data were processed by JPKSPM data processing software and analysed using SigmaPlot (Sysstat Software GmbH, Erkrath, Germany). Measurements were also performed over a plain glass surface to obtain control values.

The optical contrast images were obtained using a Leica 4200 Optical Microscopy. The Raman and photoluminescence (PL) spectra were recorded using a LabRAM HR Evolution Raman system with 532 nm laser excitation. The laser power at the sample was lower than 0.5 mW to avoid any laser-induced heating. To obtain the Raman images, an X-Y stage was used to move the sample with a 200 nm step, and the corresponding Raman spectrum was recorded at every point. AFM is carried out using a Bruker Dimension ICON system in the tapping mode.

Confocal micrographs are acquired by an inverted microscope Eclipse Ti equipped with a confocal A1R-MP system (Nikon), using an Argon ion laser (excitation wavelength, λ = 488 nm). The sample emission is collected by a 60× (oil immersion NA = 1.40, Nikon) objectives and the fluorescence signal is detected by a spectral detection unit equipped with a multi-anode photomultiplier (Nikon).
The AFM characterization of the nanopatterned surfaces is carried out by “peak force” imaging mode in air using a Bruker Dimension Icon system equipped with a Nanoscope V controller. The used silicon tip (nominal radius of curvature of 2 nm) is mounted on silicon nitride cantilever with 0.4 N/m nominal spring constant. SEM is performed with a Nova NanoSEM 450 system (FEI), using an acceleration voltage around 8 kV and an aperture size of 30 mm.