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Congratulations to Jonas Schwan on the publication of his paper in Crystals! The manuscript is part of the Special Issue "Women in Mineralogical Crystallography and Biomineralization" and elucidates the dewetting of electrochemically deposited cobalt hydroxide films and their self-rolling into 3-dimensional, self-supported spirals.

Strain-induced self-folding is a ubiquitous phenomenon in biology, but is rarely seen in brittle geological or synthetic inorganic materials. We here apply this concept for the preparation of three-dimensional free-standing microscrolls of cobalt hydroxide. Electrodeposition in the presence of structure-directing water-soluble polyelectrolytes interfering with solid precipitation is used to generate thin polymer/inorganic hybrid films, which undergo self-rolling upon drying. Mechanistically, we propose that heterogeneities with respect to the nanostructural motifs along the surface normal direction lead to substantial internal strain. A non-uniform response to the release of water then results in a bending motion of the two-dimensional Co(OH)₂ layer accompanied by dewetting from the substrate. Pseudomorphic conversion into Co₃O₄ affords the possibility to generate hierarchically structured solids with inherent catalytic activity. Hence, we present an electrochemically controllable precipitation system, in which the biological concepts of organic matrix-directed mineralization and strain-induced self-rolling are combined and translated into a functional material.

Read more on this research here.