Microfluidic generation of tunable emulsions for templated monodisperse silica

This paper describes a new approach to the formation of macroporous silica, templated using emulsions generated in a microfluidic device. With precise control over the size and uniformity of the emulsion droplets, we are able to tailor the pore size and size distribution of the resulting bulk silica gels. Using triethylenetetramine as a biomimetic catalyst, our gelation reactions occur within minutes at room temperature and neutral pH, in contrast to conventional sol-gel routes. Subsequent drying at 50°C and calcining at 400°C yields glassy materials with spherical pores where the emulsion droplets had been. Monodisperse porous silica with a range of pore sizes from 5-50 μm and polydispersity less than 2.4% has been fabricated. Such materials may be produced in situ within lab-on-a-chip systems and functionalized for use in reaction and separation modules.