Bottom-up Approach toward Titanosilicate Mesoporous Pillared Planar Nanochannels for Nanofluidic Applications

Abstract

Nanofluidic transport in lab-on-chip devices requires nanochannels that are difficult to fabricate since they require challenging top-down technological approaches. We present a bottom-up, scalable, low-cost, and robust alternative to construct large areas of extremely homogeneous Pillared Planar Nanochannels (PPNs) for nanofluidic applications. Their unique structure is made of mesoporous titanosilicate pillars, of 20 nm in diameter, supporting a continuous sealing layer of the same material. This complex hierarchical structure is achievable when combining diverse bottom-up processing strategies that include self-assembly of block copolymer, nanostructured sol−gel coatings, and highly controlled liquid deposition processing, with powerful top-down techniques such as deep X-ray lithography. While these novel materials are of interest for many nanotechnological applications, we focus on their ability to guide fluids through natural capillary forces, for which the classical Washburn’s model of diffusion is verified. These systems are the first promising example of fully mesoporous materials applied to nanofluidics, thus opening the “lab-on-chip” domain to mesofluidics.