Ionic Diffusion, Nanoparticle Formation and Trapping Within Sol‐Gel Made Pillared Planar Nanochannels in a Simple Microfluidic Device

Abstract

Efforts to obtain widespread applications in the field of nanofluidics are increasing in intensity in recent years. However, high cost production of nanofluidic devices through the commonly used nanofabrication technologies and the incomplete understanding of solute confinement is still delaying the development of reliable, reproducible and affordable nanofluidic tools. The concentration of species and their diffusion dynamics are strongly influenced by the nanostructure architecture and surface chemistry. Testing a large number of known geometries and surface characteristics has not been possible due to limitations in fabrication procedures. Here, we try to overcome these fabrication difficulties by making the production of large scale nanofluidic devices more viable. We use an alternative bottom‐up method based on supramolecular self‐assembly and sol‐gel chemistry to produce and integrate controlled ceramic nanoporous Pillar Planar Nanochannels (PPN) within microfluidic devices. The system provides a way to easily analyze the diffusion and reaction of species in the aforementioned nanochannels. We show how to extract the nano‐confined concentration and diffusion speed without requiring any expensive analysis instrument. Subsequently, large data sets can be obtained due to the affordability of the presented nanostructure and the ease of its analysis. Moreover, since PPNs have a periodical and regular geometry the obtained data can be compared with simulations, allowing for a better description of the nanoconfined behavior of species.