"Remote" fabrication via three-dimensional reaction-diffusion: Making complex core-and-shell particles and assembling them into open-lattice crystals

A method of fabricating symmetry mismatched Core and Shell Particles (CSP) by Reaction Diffusion (RD) in either aqueous or organic environments has been reported. Polymeric or hydrogel particles of desired shapes are initially loaded uniformly with an additive material (metal micro-or nanoparticles) and removed by chemical reaction propagating inwards from the particles' surfaces. The Average size of the particles was determined by Transmission Electron Microscopy (TEM) of thin slices of the loaded agarose particles. The assembled structures were made permanent by immersing them in either liquid PDMS prepolymer or in hot agarose that were subsequently cured to gel at room temperature. This procedure can be used to fabricate a variety of complex shapes and structures, and can also be combined with self-assembly to arrange the core-and-shell particles into open-lattice crystals.