Spider Webs Offer Biomimetic Inspiration for Dew Catchers in Developing Countries

wet spider web photo

Photo via Niffty.. via Flickr CC

With the help of a scanning electron microscope, Chinese scientists have figured out the secret architecture to spiders' webs that make them incredibly effective at catching dew. Cracking into the mystery could mean that the same structures can be duplicated in fog catchers for developing nations, creating effective yet inexpensive methods for helping communities with scarce or polluted water sources. PhysOrg reports how it works: "The secret... lies in the silk's tail-shaped protein fibres which change structure in response to water. Once in contact with humidity, tiny sections of the thread scrunge up into knots, whose randomly arranged nano-fibres provide a roughly, knobbly texture. In between these "spindle knots" are joints, which are smooth and slender, comprising neatly aligned fibres.Small droplets then condense randomly on the spider's web. Once they reach a critical size, the droplets slide along the slick-surfaced joints thanks to surface tension. The droplets then reach the spindle knots, where they coalesce with larger drops. As a result, the joints are freed up to begin a new cycle of condensation and water collection."

Though they've figured out the how, the researchers are still unsure about the why behind spiders developing silk for this water-catching ability. Guesses include that the spiders then don't have to leave the web to find water, or that it keeps the web intact by distributing the weight of the water. Regardless, the structure has already been successfully mimicked.

After figuring out the secret, the scientists have been able to replicate the architecture of the web. Lei Jiang, lead researcher of the team at the Chinese Academy of Sciences in Beijing states, "Our artificial spider silk not only mimics the structure of wet-rebuilt spider silk but also its directional water collection capability." The research has been published in Nature.
Fog and dew collectors are an excellent way for people in developing nations to get clean water. A project in Peru is showing how harvesting fog can greatly benefit people who would otherwise not have access to water at all, or it would come at an exorbitant price. If this artificial spider silk can be made into inexpensive and durable dew catchers, it could be a fantastic boon for communities globally.

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