Taking inspiration from water-dwelling spiders, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed an innovative material that remains dry underwater and resists adhesion by bacteria and marine organisms.
The Science Behind It
This material is based on the remarkable adaptation of the Argyroneta aquatica, also known as the diving bell spider, which thrives underwater by using water-repellent hairs to create a protective air layer around itself. Researchers harnessed this natural mechanism to create a stable underwater plastron on a metallic surface.
Engineering a Superhydrophobic Surface
To achieve this, they engineered an aerophilic titanium alloy surface capable of attracting and releasing air or gas bubbles. By employing electrochemical oxidation to create nanoscale roughness and simultaneously forming an oxide layer through chemical dissolution, they replicated the spider’s strategy in a laboratory setting.
Testing Durability and Effectiveness
The researchers rigorously tested the stability of this surface by subjecting it to various challenges. They bent, twisted, exposed it to hot and cold water, and even abraded it with sand and steel, yet it remained aerophilic. Impressively, it maintained its properties for over 208 days of continuous submersion in water without any observable signs of degradation. Furthermore, it demonstrated its effectiveness by resisting bacterial growth, deterring barnacle attachment, and preventing mussels from adhering.
The researchers highlight that this easily manufacturable and scalable surface material holds great promise for a wide range of applications.