Faux leather stains badly and sticky vinyl sets rarely go with bare legs on a summer's day. Thankfully, there may now be an alternative for people who like the look and feel of leather but prefer not to require it be derived from a living thing. Researchers at The Ohio State University have taken inspiration from the incredibly hydrophobic surface of the lotus leaf to come up with a new leather-like material.
The team previously used a nano-engineered texture based on the leaves of this water-repelling plant to create self-cleaning glass and a mesh that can separate oil from water. In their latest work, described in the journal Colloids and Surfaces A, they describe a method for adapting the same biomimetic coating they used before to create a polymer-based synthetic leather that repels both oil and water and precludes it from becoming sticky up to a temperature of around 70 degrees Celsius.
The material might be used for easier to clean furniture, vehicle interiors, fashion accessories, shoes and indeed any product where synthetic leather is used. The research was led by Bharat Bhushan.
"Genuine leather has been an important material since the beginning of human history," Bhushan explains. "Today, the market for synthetic leather is growing [partly] because it's less expensive and easier to work with. To our knowledge, this is the first time anyone has managed to fabricate synthetic leather that is not just water resistant, but super-liquiphobic-it repels both water and oil-based liquids."
Synthetic leather is usually made from a textile fabric coated with a plastic, such as polyurethane (PU) or polyvinyl chloride (PVC). These polymers lend themselves to being molded into flat sheets that can have a leather-like texture in them. But, just as with genuine leather, these fabrics are prone to staining and become sticky when hot. To modify artificial leather, the team has sprayed silica nanoparticles on to the surface of ultraviolet-treated synthetic leather to create an improved coating. The ultraviolet treatment is the same as that commonly used in computer chip manufacturing and cleans the surface thoroughly allowing the nanoparticles to stick.
In tests with water and oil droplets the new coated artificial leather proves itself. It is also durable and heat resistant. The coated material can readily repel black silicon carbide powder allowing a 90% brush-off compared with 10% on untreated artificial leather. The stickiness of the material is also usefully reduced so that it retains its integrity up to about 70 degrees Celsius, above this and at the highest temperatures you might get in a car, the underlying polymer becomes viscous.
David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".