Alternating silica/polymer multilayer hybrid microspheres templates for double-shelled polymer and inorganic hollow microstructures

Abstract

Alternating silica/polymer tetra- and penta-layer hybrid microspheres were first prepared via combined inorganic sol-gel reaction and distillation- precipitation polymerization. pH-responsive poly(methacrylic acid) (PMAA) hollow microspheres with asymmetric double-shells were produced afterHF etching of the silica layers in the SiO2/PMAAtetra-layer microspheres with different degrees of cross-linking in the two PMAA layers. On the other hand, silica "core-double shell" hollow microspheres were obtained by calcination of the alternating silica/PMAApenta-layer microspheres. The resulting hollow polymer and silica microspheres with hierarchical structures were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) analysis, dynamic laser scattering (DLS), and confocal laser scanning microscopy (CLSM) measurements.©2010 American Chemical Society.