Xe 100 microscope

AFM analysis was made using an XE-100 microscope from Park Systems (Suwon-si, South Korea) in non-contact mode. Sharp tips, NCHR from NanosensorsTM, with typically ~8 nm radius of curvature, ~125 mm mean length, 30 mm mean width, ~42 N/m force constant, and ~330 kHz resonance frequency was used. The image processing and roughness evaluation were performed using the XEI program (v 1.8.0) from Park Systems. The detailed surface profile of the scanned films was presented in “enhanced contrast” view mode.

SEM micrographics performed on samples were recorded using a high-resolution microscope, FEI Quanta 3D FEG instrument (FEI), operating in high vacuum mode with an accelerating voltage of 1 kV. Samples were placed on double-sided conductive tape and scanned without special preparation. The surface roughness of these membranes was investigated in contact mode by atomic force microscopy (AFM) using the XE-100 microscope from Park Systems, equipped with flexure-guided, cross-talk eliminated scanners. All AFM images were recorded with pre-mounted NSC36/Hard Al BS tips (MikroMash) with rotated tip shape, full cone angle of 40°, a radius of less than 20 nm, height ~ 15 mm, 90 mm mean length, 32.5 mm mean width, ~2 N/m force constant, and thickness ~ 1 mm. The recorded AFM images were processed using the XEI program (v 1.8.0-Park Systems) for displaying purpose and roughness evaluation. In order to increase the contrast of the morphological features, the images are presented in the so-called “enhanced contrast” view mode which uses the change of a pixel relative to its neighbors. Representative line scans are presented below the AFM images, showing, in detail, the surface profile of the scanned samples and the dimensions of the selected features (particles, pits, etc.).

SERS spectra were acquired using a homemade micro-Raman system based on an Olympus BX41 microscope (Olympus, Japan). A He-Ne laser with 633 nm radiation (Melles Griot, Australia) was used as the excitation source and the laser light was focused on the sample through a 50× objective (Mitutoyo, Japan) of the microscope. The spectra were measured with a thermodynamically cooled electron-multiplying charge-coupled device (Andor, UK) mounted on the spectrometer with a 1200 groove/mm grating (Dongwoo Optron, Korea). A holographic notch filter was used to reject the laser light (Kaiser Optical Systems, USA). The acquisition time was 1 min. SEM images were obtained from a Nova230 microscope (FEI Company). AFM images were obtained from a Park Systems XE-100 microscope.