Su5000 field emission scanning electron microscope

The morphology of the nanoparticles was determined by using scanning electron microscopy. NP suspension (5 μL) was placed on the cleaned silicon wafer chip (SPI Supplies, USA) (Cat no. 4136SC-AB) and then on aluminum stubs, air dried in fume hood for 60 min and kept overnight under vacuum. Samples were coated with platinum for up to 30 nm thickness in the Q150T plus sputter coater (Quorum Technologies, UK) and imaging was done on the Hitachi SU5000 Field emission scanning electron microscope.

The specimen for metallographic characterization was cut from the cast piece, as shown in Figure 1b, ground by silicon carbide sandpaper up to 2000 grit, polished and etched with corrosion agent (hydrogen peroxide, ammonia, water, 1:1:3). The microstructure was characterized by a ZEISS optical microscope (ZEISS, Oberkochen, German) and a HITACHI SU 5000 field-emission scanning electron microscope (HITACHI, Tokyo, Japan) with the accelerating voltage of 20 kV under both secondary electron and back-scattered electron modes, and the element distribution was measured with a Bruker energy-dispersive spectrometer (EDS) (Bruker, Karlsruhe, German).

SEM was utilised to examine the coating topography of the 2D glass substrates deposited with the PEI, PDDA and CHI coatings. Prior to examination, the samples were coated with a conductive layer of gold palladium using a sputtering system (Emitech K500X, Quorum Technologies, Lewes, UK) at 25 mA for 2 min. Micrographs were collected by a Hitachi SU5000 field emission scanning electron microscope (SEM) (Hitachi, Tokyo, Japan) under a high vacuum in the secondary electron (SE) mode, with an accelerating voltage of 4 keV, to maximise the surface sensitivity. An energy-dispersive X-ray (EDX) analysis was then conducted under the same conditions. A total of 3 areas of each surface were examined at a resolution of 1024 × 1024, and the analysis was performed using the Aztec software (Oxford Instruments, Abingdon, UK). This analysis was performed at 4 keV, which corresponds to an electron range of approximately 600 nm in a polymeric material of a similar density. Therefore, only the coating, specifically the NC, was detected, without obtaining a contribution from the underlying glass substrate.