Zetasizer

The surface morphology and size of the microcapsules were characterized using field emission scanning electron microscopy (FESEM; Mira3 Inc., Brno, Moravia, Czech Republic). For this purpose, a layer of gold was coated on the samples under vacuum before observation [19 (link)]. The average zeta potential of the microcapsules was also determined using a zeta-sizer (Horiba, Fukuchiyama, Kyoto, Japan) in accordance with Tan et al. [25 (link)].

FT-IR spectra were recorded using a Shimadzu-8400S spectrometer (Japan) in the wavenumber range of 400–4000 cm⁻¹. The structure and level of crystallinity of samples were determined by using a Philips 8440 X-Pert X-ray diffractometer (Netherland), operating at 40 mA and 40 kV with copper radiation (k = 0.1542 nm). UV-vis spectra were recorded on a Carry 100 Varian spectrophotometer (USA). N₂ adsorption–desorption isotherms and BJH pore-size distribution plots of samples were determined by using a Micro metrics PHS-1020 instrument (Japan) at 77 K. The degassing process of samples was performed at 150 °C. The magnetic properties of samples at 27 °C within the range of ±15 000 Oe was carried out using a vibrating magnetometer (Iran). The surface charge of the materials was investigated by zeta potential measurements on a HORIBA Scientific Zetasizer (Japan). A MIRA3 TESCAN scanning electron microscope (Czech) was employed to examine the morphology of the prepared materials, while X-ray energy analysis (EDX) was utilized for elemental analysis of the samples.