A new material that looks just like an ordinary liquid can be shaped, moulded and sliced like Play-Doh or plasticine. It could be used to make novel lenses or mini containers for chemical reactions.
Shape-holding liquids called liquid marbles have been developed before, by coating water droplets in a hydrophobic powder. But the powder made them opaque and they were always spherical. Xiaoguang Li of Tongji University in Shanghai, China, and his colleagues wanted to remove these restrictions and make one that was transparent and mouldable.
To do so, the team created layers of silica 20 nanometres thick, then placed water droplets on top. This coated each droplet in a single layer of silica particles. “The droplet is as transparent as a pure liquid,” says Li. “The team could manipulate the liquid into any shape, including slicing it up and spelling out ‘water’“
Once applied, the particles bunch together, holding the water inside. The team found they could manipulate these conglomerations into any shape they liked, including slicing them up and spelling out “water”. They call the material liquid plasticine (Soft Matter, doi.org/bb7w).
Since the droplets are convex, they could potentially act as a liquid magnifying lens, says Li. Chemicals encased in the droplets took time to diffuse through the material, slowing down chemical reactions and making the droplets good as mini test tubes.
“Their high transparency facilitates observation of the biochemistry process, which is a significant challenge for liquid marbles,” says Li. He believes there are other effects on chemistry waiting to be discovered.
Source: New Scientist