2, University of Basel, Basel, , Switzerland
5, Paul Scherrer Institut, Villigen, , Switzerland
3, Budapest University of Technology and Economics, Budapest, , Hungary
4, Eötvös Loránd University, Budapest, , Hungary
"Printing" typically boils down to synthesis and spatial allocation of droplets and particles after a given pattern. Synthesis and spatial arrangement of nano-and microparticles of different size is important in designing nanostructured materials with functional properties. Wet synthesis methods lack flexibility to create various sizes of particles (particle libraries) using fixed conditions without the repetition of the steps of the method with a new set of parameters. Here, we report a new method where we arrange particulates from a liquid by using the competition and interplay of diffusion, chemical reaction and subsequent precipitation. The patterns develop by self-organization and needs no further manipulation than initial allocation of chemical sinks and sources. The synthesis method is based on nucleation and particle growth in the wake of a moving chemical front in a gel matrix. The process yields well-separated regions (bands) filled with mono-disperse nano-and microparticles, with the size of particles varying from band to band in a predictable way. The smallest particle size which we can report is below 300 nm. The smallest band separation is 25 micrometer. This method represents a new approach and a promising tool for competitive, fast, up-scalable, low-cost printerless printing of various sizes of colloidal particles with magnetic, optical, electrical and catalytic properties.