Dimension 3100 nanoscope 5

The morphologies of the Cu/CuO_x/Cu nanodots were observed using a field emission scanning electron microscope (FE-SEM; JSM 7401F, JEOL). The microstructure and crystal structure of nanodots were investigated using a high-resolution transmission electron microscope (HR-(S)TEM-I; JEM 2100F with a Cs corrector on STEM, JEOL) and by x-ray diffraction (XRD, D/MAX-2500/PC, RIGAKU) using Cu Kα radiation (λ  =  1.54178 Å). Before the TEM investigations, the samples were prepared using a focused ion beam (FIB; Helios, FEI).The surface morphologies of Cu/CuO_x/Cu were examined using AFM (Dimension 3100 +  Nanoscope V, VEECO) in non-contact mode and the electrical properties were measured using conductive AFM (XE-100, Park systems) in contact mode; the scan rate was 1 Hz, the scan configuration was 256 ×  256 pixels, and the scan size was 500 nm ×  500 nm. The AFM measurements were performed at room temperature and atmospheric pressure. Micro- cantilevers (length : 225 μ m, Park Systems) with frequency of 75 kHz, a spring constant of ~2.8 N m⁻¹ and a radius of curvature of ~25 nm were used.

Proton nuclear magnetic resonance (NMR) spectra were recorded on a Varian Mercury-400 NMR spectrometer (400 MHz) in D₂O using tetramethylsilane (TMS) as a reference. The particle sizes and zeta potentials of complexes at weight ratio 10 were determined using a commercial laser light scattering instrument (Malvern ZEN3690, Malvern Panalytical Ltd., Cambridge, UK) at room temperature. The hydrodynamic diameter of nanogels was measured from 25–80 °C with 2 °C intervals [45 (link)]. The morphologies of nanogels were characterized through atomic force microscopy (AFM) imaging (Dimension 3100 Nanoscope V, Veeco, Plainview, NY, USA). DNP cantilevers (k = 0.24 N/m) were operated in the air using contact mode.