Bubble-guided chemical gardens growth in a confined space: straight tubes, worms and helices

Abstract

In three-dimensional tanks, the bubble-guided growth of chemical garden tubes can be quite erratic. Here, we experimentally analyze the bubble-guided growth of such chemical gardens in quasi one-dimensional geometries using a co-flow microfluidic reactor. The confined environment tames the precipitation such that hollow straight tubes or thicker worm-like tubes can be obtained. In some regions of the parameter space spanned by the flow rate and the ratio of the bubble diameter to the inner width of the host capillary, an oscillatory motion of the bubble drives the growth of helices.