1. Could you explain the significance of your article to the non-specialist? 

The tubular precipitation structures in so-called silica gardens are known to many scientists and non-scientists alike. However, little is known regarding their growth dynamics and chemical composition. Recently, we developed a rather simple experimental set-up that allows growing such tubes in a reproducible fashion. Here, we describe the composition and morphology of the tube material using techniques such as transmission electron microscopy and vibrational spectroscopy. Specifically, we find that the tube wall consists of metal hydroxide that is stabilized by a thin, exterior silica layer. After synthesis the tubes can be further modified using chemical and/or physical means. 

2. What has motivated you to conduct this work? 

The formation of precipitation tubes have a very long history in chemistry that dates back at least into the 17th century. Although some qualitative aspects are well understood, we are far away from a systematic or semi-quantitative understanding. Our group attempts to unravel the underlying laws and mechanisms and also explores potential application of the overall process. Moreover, we are curious about similarities of our experiments and tubular structures in geochemical and biological systems such as black smokers at hydrothermal vents and marine algae. 

3. Where do you see this work developing in the future? 

Being able to create such structures on a micrometer-scale would open up many promising research directions. For us, however, the main goal remains to develop a thorough and satisfying understanding of the overall process and main growth regimes. 

4. Are there any particular challenges facing future research in this area? 

From a theoretical point of view, the real growth mechanism is a free-boundary problem that is not easy to model in mathematical terms.