TY - JOUR
T1 - Growth of mesoporous silica nanoparticles monitored by time-resolved small-angle neutron scattering
AU - Hollamby, Martin J.
AU - Borisova, Dimitriya
AU - Brown, Paul
AU - Eastoe, Julian
AU - Grillo, Isabelle
AU - Shchukin, Dmitry
PY - 2012/3/6
Y1 - 2012/3/6
N2 - Since the first development of surfactant-templated mesoporous silicas, the underlying mechanisms behind the formation of their structures have been under debate. Here, for the first time, time-resolved small-angle neutron scattering (tr-SANS) is applied to study the complete formation of mesoporous silica nanoparticles. A distinct advantage of this technique is the ability to detect contributions from the whole system, enabling the visualization not only of particle genesis and growth but also the concurrent changes to the coexistent micelle population. In addition, using contrast-matching tr-SANS, it is possible to highlight the individual contributions from the silica and surfactant. An analysis of the data agrees well with the previously proposed "current bun" model describing particle growth: Condensing silica oligomers adsorb to micelles, reducing intermicellar repulsion and resulting in aggregation to form initial particle nuclei. From this point, the growth occurs in a cooperative manner, with condensing silica filling the gaps between further aggregating micelles. The mechanistic results are discussed with respect to different reaction conditions by changing either the concentration of the silica precursor or the temperature. In doing so the importance of in situ techniques is highlighted, in particular, tr-SANS, for mechanism elucidation in the broad field of materials science.
AB - Since the first development of surfactant-templated mesoporous silicas, the underlying mechanisms behind the formation of their structures have been under debate. Here, for the first time, time-resolved small-angle neutron scattering (tr-SANS) is applied to study the complete formation of mesoporous silica nanoparticles. A distinct advantage of this technique is the ability to detect contributions from the whole system, enabling the visualization not only of particle genesis and growth but also the concurrent changes to the coexistent micelle population. In addition, using contrast-matching tr-SANS, it is possible to highlight the individual contributions from the silica and surfactant. An analysis of the data agrees well with the previously proposed "current bun" model describing particle growth: Condensing silica oligomers adsorb to micelles, reducing intermicellar repulsion and resulting in aggregation to form initial particle nuclei. From this point, the growth occurs in a cooperative manner, with condensing silica filling the gaps between further aggregating micelles. The mechanistic results are discussed with respect to different reaction conditions by changing either the concentration of the silica precursor or the temperature. In doing so the importance of in situ techniques is highlighted, in particular, tr-SANS, for mechanism elucidation in the broad field of materials science.
UR - http://www.scopus.com/inward/record.url?scp=84857809955&partnerID=8YFLogxK
U2 - 10.1021/la203097x
DO - 10.1021/la203097x
M3 - Article (Academic Journal)
C2 - 22044300
AN - SCOPUS:84857809955
SN - 0743-7463
VL - 28
SP - 4425
EP - 4433
JO - Langmuir
JF - Langmuir
IS - 9
ER -