Controlled Fabrication and Water Collection Ability of Bioinspired Artificial Spider Silks

摘要

Collecting water from fog is a feasible route to solve the problem of water shortage, especially in dry and fog-laden areas.~([1-7])In nature some creatures have developed the amazing ability to collect water owing to special micro- and nanostructures on their surfaces, such as desert beetles~([8]) and cribel-late spiders.~([9]) The desert beetle's back is patterned with hydrophobic and hydrophilic regions. Water droplets first condense on the hydrophilic region and then roll off the back because of gravity. Some research has been carried out to mimic the beetle's back by collecting water on bioinspired two-dimensional substrates with patterned wettability.~([10-12]) Following a different mechanism, spider silk, which has outstanding mechanical properties,~([13]) is also suited for collecting water from fog, as is well known from the shiny water droplets hanging on a spider's web in the early morning. The captured silk of cribellate spiders deforms to have a unique wet-rebuilt "spindle-knots/joints" structure, which induces the cooperation between surface energy gradient and curvature gradient.~([9]) This enables the silk to drive tiny water droplets (no more than 100 um in size) directionally from the "joints" to the "spindle-knots" during the water collection process. In our previous studies,~([9,14,15]) we successfully reproduced these structural features on bioinspired