Microfluidics-mediated self-template synthesis of anisotropic hollow ellipsoidal mesoporous silica nanomaterials

Abstract

Herein, a facile strategy was firstly developed to synthesize ellipsoidal mesoporous silica nanomaterials (MSNs) with well-ordered parallel channels along the short axis. A miniaturized microfluidic device with spiral-shaped channels was then chosen as a straightforward and general platform to produce the corresponding hollow counterparts of MSNs under mild conditions. Such reaction process carried out in a microfluidic system was further demonstrated to be more rapid and efficient than a conventional batch method under equivalent experimental conditions. The evolution of hollow structure can be well tuned by flow rates (i.e. etching time), providing a new paradigm for rational design and engineering of anisotropic nanostructures. IMPACT STATEMENTThis study developed a straightforward and general microfluidic platform to produce hollow nanostructures, providing new routes for rational design and engineering of functional nanomaterials. ARTICLE HISTORY

Microfluidics for silica biomaterials synthesis: opportunities and challenges

“…[10,51-62] Despite of great needs, controllable synthesis of nonspherical silica materials remains a significant challenge. Our research group first opened up this area using spiralshaped microreactors with two-inlet flows and fabricated a series of nonspherical silica materials, including hollow ellipsoid, 54 fiber, 57 flower, 58 sheet, 60 and triangle. 61 Microfluidic synthesis of anisotropic hollow ellipsoidal mesoporous silica nanomaterials was realized by a self-templating method.…”

“…Comparatively, the batch reactor should need nearly one day. 54 Using the templating methods, microreactor can be employed as a general and straightforward platform for the synthesis of hollow cube, hollow rod, hollow belt, and other anisotropic hollow silica materials. 59 By choosing specific reactants as inlet fluids, we found that nonspherical silica materials can be collected directly from the outlet at certain flow rates.…”

“…Compared to post-synthesis batch loading approach of drugs, 54,56,120 microfluidic approach permits one-step encapsulation of aqueous insoluble and aqueous soluble drugs during the formation of resultant silica-based biomaterials, which significantly simplifies the drug loading procedures. 111,122 To achieve sustained drug delivery, microfluidics can encapsulate drug-loaded thermally hydrocarbonized porous silicon (THCPSi) microparticles within solid lipid microparticles (SLMs).…”

“…There have only been very few direct investigations to date showing the advanced merits of microreactors in terms of faster reaction kinetics, narrower particle size distributions, higher reproducibility, and larger application capacity. 41,43,44,46,54,60 More parallel studies are in need to examine the differences between microfluidic reaction and batch reaction.…”

Functionalized Silicas for Metal‐Free and Metal‐Based Catalytic Applications: A Review in Perspective of Green Chemistry

“…These silicas, on comparison with each other, exhibit different porosity, stability, particle size and surface area. Not only porosity and surface area, note that the morphology of silica can also be tuned to different shapes such as spheres, cubes, rods, ellipsoids, nanotubes, fibres, silica sheets and silica leaves . Comparison between the properties (pore structure, stability under different conditions, particle size and morphology) of various silicas (KCC‐1, MCM‐41, SBA‐15 and Stöber silica) can be better understood from the review article of Maity and Polshettiwar.…”