Synthesis of hollow BaSO₄nanospheres templated by core–shell–corona type polymeric micelles

Abstract

Hollow barium sulfate (BaSO 4 ) nanospheres were synthesized by templating a polymeric micelle of a triblock copolymer poly(styrene-b-acrylic acid-b-ethylene glycol) (PS-b-PAA-b-PEG). This polymer is known to form a micelle with a PS core, a PAA shell and a PEG corona in aqueous solutions. Barium chloride and sodium sulfate were used as precursors of BaSO 4 . In the synthesis, the PS core acts as a template for cavities of the hollow particles, the PAA shell is beneficial for arresting Ba 2+ ions to produce BaSO 4 , and the PEG corona stabilizes the BaSO 4 /polymer nanocomposite to prevent secondary aggregate formation. Hollow BaSO 4 nanospheres were obtained by removing the polymeric template from the BaSO 4 /polymer nanocomposite by calcination. The hollow BaSO 4 nanospheres thus fabricated were characterized by various techniques including transmission electron microscopy and X-ray diffraction analysis. The average diameter of the spheres is around 25 nm and the average cavity diameter is around 16 nm. The significance of the present method is that it can avoid formation of large crystals which is generally unavoidable in other methods.

Synthesis of a Large‐Sized Mesoporous Phosphosilicate Thin Film through Evaporation‐Induced Polymeric Micelle Assembly

“…Uniformly distributed spherical micelles were clearly seen (Figure 2a). The zeta‐potential measurement was carried out to determine the surface charge of the micelles, which provides useful information about the interaction of inorganic precursors with polymeric micelles 18. 19 For neat polymeric micelles, the zeta‐potential value was approximately 30 mV.…”

Engineering biodegradable micelles of polyethylenimine-based amphiphilic block copolymers for efficient DNA and siRNA delivery

“…Incorporation of PEG-CG during micelle formation could strongly affect the micelle-DNA interactions, as both particle size and zeta potential were altered at the presence of PEG-CG. It has been suggested that the PEG corona could prevent the aggregation of micelles or micellebased nanocomposites due to a steric repulsion between the PEG chains [42][43][44][45]. This may explain that sizes of polyplex particles containing PEG-CG were smaller than those without PEG-CG for most of the N/P ratios ( Fig.…”

Asymmetric Block Copolymers for Supramolecular Templating of Inorganic Nanospace Materials

“…Safety and toxicological issues of the hollow nanospheres were confirmed by using tetra­zolium‐based colorimetric (MTT) assays of a breast cancerous cell line (BT‐20). In addition, PS‐PAA‐PEO micelles were applied for synthesizing hollow nanospheres with different compositions such as CaCO 3 , BaSO 4 , TiO 2 , Fe 2 O 3 , and La 2 O 3 . The in‐vitro delivery of drugs using hollow CaCO 3 nanospheres showed a gradual and sustained release behavior of drugs over a period of 60 h with a retention time of 27 h .…”