Icicles and stalactites grow little by little, each layer a testament to the object’s history. Here, researchers explore a similar phenomenon, grown from a dripping liquid. They’re called “flexicles” in homage to their natural counterparts, and they start from a thin layer of elastomer liquid. Though it begins as a liquid, elastomer solidifies over time.
To form flexicles, the researchers spread a layer of elastomer on an upside-down surface and allow gravity to do its thing (above). Thanks to the Rayleigh-Taylor instability, the dense elastomer forms a pattern of drips that, after hardening, creates a pebbled surface. Subsequent layers of elastomer will drip from the same spots as before, slowly growing longer flexicles (below). The team envisions using them for soft robotics, but, personally, I just really want poke at them and wiggle them. (Image and research credit: B. Venkateswaran et al.; via APS Physics)