Engineering the internal structure of magnetic silica nanoparticles by thermal control

Handle URI:
http://hdl.handle.net/10754/563766
Title:
Engineering the internal structure of magnetic silica nanoparticles by thermal control
Authors:
Song, Hyon Min; Zink, Jeffrey I.; Khashab, Niveen M. ( 0000-0003-2728-0666 )
Abstract:
Calcination of hydrated iron salts in the pores of both spherical and rod-shaped mesoporous silica nanoparticles (NPs) changes the internal structure from an ordered 2D hexagonal structure into a smaller number of large voids in the particles with sizes ranging from large hollow cores down to ten nanometer voids. The voids only form when the heating rate is rapid at a rate of 30 °C min-1. The sizes of the voids are controlled reproducibly by the final calcination temperature; as the temperature is decreased the number of voids decreases as their size increases. The phase of the iron oxide NPs is α-Fe2O3 when annealed at 500 °C, and Fe3O4 when annealed at lower temperatures. The water molecules in the hydrated iron (III) chloride precursor salts appear to play important roles by hydrolyzing Si-O-Si bonding, and the resulting silanol is mobile enough to affect the reconstruction into the framed hollow structures at high temperature. Along with hexahydrates, trivalent Fe3+ ions are assumed to contribute to the structure disruption of mesoporous silica by replacing tetrahedral Si4+ ions and making Fe-O-Si bonding. Volume fraction tomography images generated from transmission electron microscopy (TEM) images enable precise visualization of the structures. These results provide a controllable method of engineering the internal shapes in silica matrices containing superparamagnetic NPs.
KAUST Department:
Advanced Membranes and Porous Materials Research Center; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; Smart Hybrid Materials (SHMs) lab
Publisher:
Wiley-VCH Verlag
Journal:
Particle and Particle Systems Characterization
Issue Date:
30-Sep-2014
DOI:
10.1002/ppsc.201400118; 10.1002/ppsc.201570008
Type:
Article
ISSN:
09340866
Sponsors:
The authors gratefully acknowledge support from King Abdullah University of Science and Technology (KAUST) and the NSF grant DBI-1266377.
Appears in Collections:
Articles; Advanced Membranes and Porous Materials Research Center; Physical Sciences and Engineering (PSE) Division; Controlled Release and Delivery Laboratory; Chemical Science Program

Full metadata record

DC FieldValue Language
dc.contributor.authorSong, Hyon Minen
dc.contributor.authorZink, Jeffrey I.en
dc.contributor.authorKhashab, Niveen M.en
dc.date.accessioned2015-08-03T12:09:25Zen
dc.date.available2015-08-03T12:09:25Zen
dc.date.issued2014-09-30en
dc.identifier.issn09340866en
dc.identifier.doi10.1002/ppsc.201400118en
dc.identifier.doi10.1002/ppsc.201570008en
dc.identifier.urihttp://hdl.handle.net/10754/563766en
dc.description.abstractCalcination of hydrated iron salts in the pores of both spherical and rod-shaped mesoporous silica nanoparticles (NPs) changes the internal structure from an ordered 2D hexagonal structure into a smaller number of large voids in the particles with sizes ranging from large hollow cores down to ten nanometer voids. The voids only form when the heating rate is rapid at a rate of 30 °C min-1. The sizes of the voids are controlled reproducibly by the final calcination temperature; as the temperature is decreased the number of voids decreases as their size increases. The phase of the iron oxide NPs is α-Fe2O3 when annealed at 500 °C, and Fe3O4 when annealed at lower temperatures. The water molecules in the hydrated iron (III) chloride precursor salts appear to play important roles by hydrolyzing Si-O-Si bonding, and the resulting silanol is mobile enough to affect the reconstruction into the framed hollow structures at high temperature. Along with hexahydrates, trivalent Fe3+ ions are assumed to contribute to the structure disruption of mesoporous silica by replacing tetrahedral Si4+ ions and making Fe-O-Si bonding. Volume fraction tomography images generated from transmission electron microscopy (TEM) images enable precise visualization of the structures. These results provide a controllable method of engineering the internal shapes in silica matrices containing superparamagnetic NPs.en
dc.description.sponsorshipThe authors gratefully acknowledge support from King Abdullah University of Science and Technology (KAUST) and the NSF grant DBI-1266377.en
dc.publisherWiley-VCH Verlagen
dc.subjectIron oxide nanoparticlesen
dc.subjectMesoporous silicaen
dc.subjectStructure engineeringen
dc.subjectSuperparamagnetic nanoparticlesen
dc.subjectThermal controlen
dc.titleEngineering the internal structure of magnetic silica nanoparticles by thermal controlen
dc.typeArticleen
dc.contributor.departmentAdvanced Membranes and Porous Materials Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentSmart Hybrid Materials (SHMs) laben
dc.identifier.journalParticle and Particle Systems Characterizationen
dc.contributor.institutionDepartment of Chemistry and Biochemistry, University of CaliforniaLos Angeles, CA, United Statesen
dc.contributor.institutionDepartment of Chemistry, Dong-A UniversityBusan Saha-gu, South Koreaen
kaust.authorKhashab, Niveen M.en
kaust.authorSong, Hyon Minen
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