A bio-inspired flexible fiber array with an open radial geometry for highly efficient liquid transfer

Generally, highly efficient liquid transfer is difficult to achieve in open fibrous systems, as compared with traditional closed systems, because capillary coalescence frequently occurs when fiber arrays interact with a liquid. Dandelion pappi, which are flexible fiber arrays with open radial geometries, exhibit the unique ability to capture and hold large amounts of water steadily. Drawing inspirations from this natural system, we developed an artificial flexible glass fiber array with a radial geometry that is capable of holding large volumes of liquid and controllably transferring the liquid onto a substrate. The highly efficient liquid transfer of the open fibrous array can be attributed to the synergistic effects of the flexibility of fibers that radially arranged with a big open angle that enables a distinct elastic deformation of the fibers and the consequent formation of a large space within the fiber array for liquid storage, and the highly adhesive property of fibers that helps the pining of three-phase contact line on the fibers. This unique open system may provide a novel strategy for highly efficient and controllable liquid transfer. A team of Chinese researchers have looked to the dandelion pappus, which can hold 96 times its own weight in water, for inspiration. Led by Huan Liu at Beihang University in China, the researchers observed that the dandelion's radial arrays of fibrous feather-like hairs are able to capture and hold large amounts of rainwater or dew. Individual hairs were studied under the microscope and were found to have a tapered structure with microsized spines and groves on their surface. Mimicking nature, the researchers fixed flexible, textured conical glass fibers in a radial manner to a polymer rod. This artificial system demonstrated the same liquid-grabbing ability as that of dandelion pappi. Bioinspired fibrous systems of this type could offer a new approach to controllable liquid capture, manipulation and transfer. Highly efficient liquid transfer is realized using an open radial glass fibers array bio-inspired by the dandelion pappus. The highly adhesive property and the elastic nature of the fiber, together with the large open angle between the fibers, endow the open radial fibers array the ability to encapsulate huge amount of water.