Direct scanning electron microscopy-based observation of dispersed core–shell-type nanoparticles in a wet state

A new sample holder for observing non-dried samples by SEM is presented, and it is employed to investigate the effect of heating on core–shell-type ceria/polymer hybrid nanoparticles to 200 °C in air. Through this, heating is shown to reduce the shell thickness of the nanoparticles. Furthermore, despite this reduction in shell thickness, the nanoparticles maintain a good dispersibility in an aqueous solution. Some sub-micrometer sized agglomerated particles are formed, but only in those instances where the shell thickness is insufficient. This new technique is therefore confirmed as an effective means of assessing the dispersibility of nanoparticles.