Pellet-grown chemical gardens in horizontal planar confined geometry : Diffusion-controlled growth and osmotic fracture

Chemical gardens refer to a class of plant-like self-assembling inorganic precipitate structures whose growth is driven by osmosis. They are thought to be related to hydrothermal vents and the origin of life. In this work, we have investigated the dynamical behaviour of chemical gardens grown in a horizontal Hele-Shaw cell from cobalt and manganese chloride with aqueous sodium silicate. It is found that the growth of the chemical gardens is well-described by a diffusion-controlled model. In reproducible time scales, the chemical gardens exhibit explosive fracture, which we attribute to osmosis-induced pressurisation. This is similar to osmotic lysis found in biological cells.