Particle assembly via wet PDMS rubbing in pre-patterned silicon substrates for the fabrication of ordered particle arrays in microfluidic devices

Here, a wet rubbing method using a patterned rubbing tool is proposed for filling arrays of interconnected micromachined pockets with individual microspheres on rigid, uncoated silicon substrates without damaging the substrate or particles. We show that 5-10 µm silica and polystyrene particles can be assembled using this method, with a filling ratio (FR) of 99.5%. These particle arrays are entirely sunken in the structures that may be placed in a sealed environment, opening routes to microfluidic applications, such as liquid chromatography or catalysis.