Open AccessSelf-Assembly of Pluronic F127—Silica Spherical Core–Shell Nanoparticles in Cubic Close-Packed Structures
Author(s) -
Stef Kerkhofs,
Tom Willhammar,
Heleen Van Den Noortgate,
Christine E. A. Kirschhock,
Eric Breynaert,
Gustaaf Van Tendeloo,
Sara Bals,
Johan A. Martens
Publication year - 2015
Publication title -
chemistry of materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.741
H-Index - 375
eISSN - 1520-5002
pISSN - 0897-4756
DOI - 10.1021/acs.chemmater.5b01772
Subject(s) - poloxamer , small angle x ray scattering , mesoporous material , materials science , chemical engineering , copolymer , micelle , adsorption , citric acid , nanoparticle , mesoporous silica , scattering , polymer , nanotechnology , chemistry , organic chemistry , composite material , aqueous solution , catalysis , physics , optics , engineering
A new ordered mesoporous silica material (COK-19) with cubic symmetry is synthesized by silicate polycondensation in a citric acid/citrate buffered micellar solution of Pluronic F127 triblock copolymer near neutral pH. SAXS, nitrogen adsorption, TEM, and electron tomography reveal the final material has a cubic close packed symmetry ( Fm 3̅ m ) with isolated spherical mesopores interconnected through micropores. Heating of the synthesis medium from room temperature to 70 °C results in a mesopore size increase from 7.0 to 11.2 nm. Stepwise addition of the silicate source allows isolation of a sequence of intermediates that upon characterization with small-angle X-ray scattering uncovers the formation process via formation and aggregation of individual silica-covered Pluronic micelles.
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