Evaluation of the mechanical stability of core–shell structured polystyrene/mesoporous-silica (PS-mSiO₂) composite particles

Abstract

Organic–inorganic composite particles with a core–shell structure exhibit potential applications in chemical mechanical polishing for mechanically challenging materials. In this work, the core–shell structured polystyrene/mesoporous-silica (PS-mSiO₂) composite particles (413 ± 5 nm in particle size, 75–80 nm in shell thickness) were exposed to a unilateral external pressure. The impact of the mechanical pressure on their mechanical stability and structural change was evaluated by X-ray diffraction (XRD), field emission scanning electron microscopy, transmission electron microscopy, and N₂ adsorption–desorption measurements. It was found that the XRD peaks of the samples are broad and weak, and the adsorption capacity, specific area and pore volume accordingly decrease with increasing the pressure from 62 to 374 MPa. The core–shell structure is still preserved for the samples compressed at a low pressure (62.3 MPa), while partially and essentially destroyed at a relatively high pressure (155.8 and 249.2 MPa) and highest pressure (311.5 MPa), respectively. The high pressure results in disintegration of the mSiO₂ shells into small chips.