From Chemical Gardens to Chemobrionics

Chemical gardens are perhaps the best example in chemistry of a\nself-organizing nonequilibrium process that creates complex\nstructures. Many different chemical systems and materials can\nform these self-assembling structures, which span at least 8\norders of magnitude in size, from nanometers to meters. Key to\nthis marvel is the self-propagation under fluid advection of\nreaction zones forming semipermeable precipitation membranes\nthat maintain steep concentration gradients, with osmosis and\nbuoyancy as the driving forces for fluid flow. Chemical gardens\nhave been studied from the alchemists onward, but now in the\n21st century we are beginning to understand how they can lead\nus to a new domain of self-organized structures of semipermeable\nmembranes and amorphous as well as polycrystalline solids\nproduced at the interface of chemistry, fluid dynamics, and\nmaterials science. We propose to call this emerging field\nchemobrionics.