Multiscan ccd

Morphology, structure and size of synthesized NPs were characterized by the high-resolution transmission electron microscopy (HR-TEM) system (JEOL JEM 3010) operating at 300 kV and equipped with a Gatan Multiscan CCD in imaging and diffraction modes. Samples were prepared by dropping 5 μL of NPs solution onto a carbon-coated TEM copper grid and subsequent drying at ambient conditions. Analysis of selected area electron diffraction (SAED) patterns was performed using ProcessDiffraction v.8.7.1 software^{45 (link)} Uncertainty in determination of lattice constants was estimated as full width at half maximum (FWHM) of diffraction rings after lognormal correction for background signal. ζ–potential measurements were performed using a Zetasizer ZS instrument (Malvern Instruments, Orsay, France). Extinction spectra of NPs solutions were measured by a UV– VIS spectrophotometer (UV–2600, Shimadzu) using 10 mm optical path length quartz cuvettes. Concentrations of NPs solutions were determined by measuring target weight before and after the ablation step. As the TiN target was produced by hot-pressing of a TiN powder and presented a porous material, a prolonged drying step was required to determine the mass change correctly. Additional concentration measurements were done using the inductively coupled plasma – mass spectrometry (ICP–MS) method.

Cryogenic transmission electron microscopy (cryo-TEM) observations were performed to determine the structures of microemulsions. The cryo-TEM samples were prepared in a controlled-environment vitrification system (Cryoplunge TM3, USA) at 25 °C and 95% relative humidity. A 4 mL aliquot of the sample was loaded onto a carbon-coated copper grid. The excess solution was then blotted off with filter paper, and a thin film suspended on the mesh holes was produced. After about 5 s, the sample-loaded grid was quickly put in liquid ethane (cooled by liquid nitrogen). The vitrified sample was transferred into a cryogenic specimen holder (Gatan 626) and observed using a JEM-1400 TEM (JEOL, Japan) at approximately −174 °C with an accelerating voltage of 120 kV. The images were obtained using a Gatan multiscan CCD and processed with a Digital micrograph. All samples used for cryo-TEM were filtered through a 0.45 μm filter prior to measurements.