Figure 2

Characterizations of the prepared beads. (A) FT–IR spectra of the prepared beads. The dashed lines, (i) and (ii), indicate the peaks attributed to the C=O stretching and N–H bending vibrations, respectively. (B) Zeta potential of the prepared silica beads (n = 3). (C) SEM images of the prepared beads where the scale bars = 2 μm. (Figures were drawn Microsoft PowerPoint 2019 Version 2112).