What if we solve society's problems by looking at nature's toolbox? We continue our series with a focus on superhydrophobicity, and investigate how it can help keep optical equipment functioning in an optimum manner in the harshest conditions.

What is superhydrophobicity?

© Thales

“Picture a lotus leaf” encourages Julie Cholet, Research Engineer at Thales. “When water lands on the surface it adopts a spherical configuration and is repelled. This is superhydrophobicity. For an object like a lotus leaf, it enables the surface to minimise its contact with water.”

This property is widely seen in nature, where certain plants and animals have evolved to repel water for survival. This so called "lotus effect" refers to the leaf's ability to self-clean due to its ultra-water-repellent surface. When a water droplet lands on the leaf, it simply beads up and rolls off, carrying dirt and debris with it—much like how wax resists water. This ability to reject water is not just limited to the lotus; many plants have evolved similar strategies to protect themselves from excess water, dirt, and pathogens, each with its unique biological purpose.

“Almost all plants and animals are hydrophobic because no living organism wants to get completely soaked,” points out Edwin Plokker, Curator at Museumfabriek (“Museum factory”), a natural history museum in Enschede in the Netherlands. “In the animal kingdom, superhydrophobicity is crucial to improve the chances of survival.”

 

Many animals, particularly insects, amphibians, and aquatic species, have developed ways to repel water. For example, water striders use superhydrophobic legs to "walk" on water, and certain frogs have water-resistant skin to prevent drowning. Birds, like penguins, have tightly packed feathers coated with oils that create a superhydrophobic surface, allowing them to stay dry in freezing waters and maintain their body heat.

Replicating natural phenomena

Such properties have inspired researchers at Thales to study how to replicate these natural phenomena. At the Group’s Research & Technology centre in Palaiseau, just south of Paris, Julie Cholet and her team focus on multifunctional surfaces that combine superhydrophobic properties with other functionalities, such as antireflective surfaces, inspired by insects like the Greta oto butterfly, which has transparent wings that naturally minimise reflection and glare.

© Thales

“We take this inspiration into our clean rooms where we study micro- and nanofabrications. The possible uses for such surfaces are very wide, particularly in optical systems used in vehicles,” explains Julie Cholet. “For these Thales systems, often featuring high-performance video cameras, it offers a durable solution because you don’t need maintenance.”

Through these naturally inspired advances, the team aims to enhance performance, durability, and safety. One example where these technologies have been tested is the Gatekeeper, an electro-optic security system with cameras that need to provide ships with a continuous 360° panoramic visual overview in harsh environmental conditions. Having high-performance, durable surfaces that can withstand extreme humidity while maintaining optimal functionality can provide a key operational advantage.

“Nature developed these properties through evolution,” points out Julie. “Our research in superhydrophobicity goes back a decade, but we are already seeing great results – and it’s only just the beginning!”