Writing on solid materials, like parchment or paper, is possible because the ink binds to the surface and remains undisturbed. But in a liquid, particles are constantly moving around, and ink quickly disperses 鈥� until now.
at Johannes Gutenberg University Mainz in Germany and his colleagues have used a resin bead听to draw lines and patterns in water containing ink particles. It works because the bead produces paths of low acidity through the water that attract the ink.
To move the bead along specific paths, Palberg and his colleagues designed a platform that could be tilted from side to side to make the bead roll downhill.
Advertisement
鈥淚n order to command the word being written or pattern being drawn, you better have something you can really steer,鈥� says Palberg. 鈥淥ne choice is, of course, gravity. Gravity is always there and always works well.鈥�
As the bead moves through the water, which is sandwiched between two glass plates positioned on top of the platform, the ink particles resting on the bottom plate are attracted into the lines created by the bead. The researchers managed to form words and shapes, including the initials of Johannes Gutenberg University (see image, above) and a simple drawing of a house.
The lines began to widen after 10 minutes, but Palberg says it should be possible to fix them in place permanently using ultraviolet light. The technique could help visualise traces of chemicals in fluid, store information or be used for art, say the researchers.
鈥淚t鈥檚 a big advance, and it鈥檚 really good work,鈥� says at the University of Cambridge. He says it could also be useful for applications where expensive particles are moved to exactly where they are required for reactions in liquids.
arXiv
