Visualization of the self-assembly of silica nanochannels reveals growth mechanism

Abstract

Self-assembled mesoporous structures with well-ordered nanoscale channels could be used in applications such as molecular separation, nano-optics, molecular electronics, nanomedicine and catalysis. However, the domain sizes that can be created in such systems are limited by our lack of a detailed understanding of the relevant growth processes. Here we report the real-time observation of domain growth in the self-assembly of silica nanochannels using fluorescence polarization imaging and atomic force microscopy. We show that transient lamellar structures precede the formation of hexagonal layers, and that the layer growth follows two distinct pathways. In addition, the domains are grown on a mesoporous film substrate, which acts as a sieve and allows control of the delivery of the reactive species. We use these insights and capabilities to grow layers of well-ordered silica nanochannels with domain sizes of up to ∼0.3 mm.

Review. Fluorescence Microscopy Studies of Porous Silica Materials

“…Studies on the mechanism during film growth were also recently published by Jung et al who reported on the in situ visualization of domain growth in the selfassembly of silica nanochannels using fluorescence microscopy and atomic force microscopy (AFM) [29]. They observed well-ordered silica nanochannels with domain sizes of up to ∼0.3 mm and showed that the formation of transient lamellar structures precede the appearance of hexagonal layers.…”

“…Furthermore they discussed that the layer growth follows two distinct pathways (for details see ref. [29]). …”

Release pathways of interferon α2a molecules from lipid twin screw extrudates revealed by single molecule fluorescence microscopy

“…within mesoporous matrices in order to reveal for example the domain structure of the porous hostl [25][26][27]. In this study we used this technique to track individual fluorescently labeled recombinant human IFNα protein molecules within lipid tsc-extrudates and directly determined the real diffusion coefficients of these molecules for the first time.…”

Single Molecule Microscopy

“…Studies on the mechanism during film growth were also recently published by Jung et al who reported on the in situ visualization of domain growth in the self-assembly of silica nanochannels using fluorescence microscopy and atomic force microscopy (AFM) [112]. They observed well-ordered silica nanochannels with domain sizes of up to ≈ 0.3 mm and showed that transient lamellar structures precedes the formation of hexagonal layers.…”

“…They observed well-ordered silica nanochannels with domain sizes of up to ≈ 0.3 mm and showed that transient lamellar structures precedes the formation of hexagonal layers. Furthermore, they discussed that the layer growth follows two distinct pathways (for details see Reference [112]). …”