Coatings for Self-Cleaning Superhydrophobic, Superoleophobic, or Omniphobic Surfaces

Dichotomous Hydrophilic/Hydrophobic Particles Generate Surfaces with Contact Angle Greater than 150° to Repel Liquids and Oils

These particles with hydrophilic cores and hydrophobic agents around them disperse in water to form a coating that generates a superhydrophobic, superoleophobic, or omniphobic surface upon application. Interior and exterior surfaces such as countertops and coatings on furniture can have water, oil, and other liquids seep into them, potentially staining the surfaces permanently . All surfaces that need to be coated or painted will benefit from this composition. Available coatings or water-based paints are incapable of generating superhydrophobic, superoleophobic, or omniphobic surfaces desirable for many applications since processing aids are needed to make them compatible with water, which render them hydrophilic after drying.

Researchers at the University of Florida have developed composite hydrophilic-hydrophobic particles that disperse in water, creating a superhydrophobic, superoleophobic, or omniphobic surface coating on drying. The superhydrophobic, superoleophobic, and omniphobic surfaces will be easy to clean because droplets of water, oil, and other liquids will not seep into them. Coated surfaces have a contact angle greater than 150°, repelling almost all liquid droplets. Droplets will collect contaminants such as dust and dirt while rolling off the surface, making it self-cleaning.

Application

Superhydrophobic, superoleophobic, or omniphobic surfaces that self-clean when water, oil, and all other liquids get on the surface

Advantages

• Water based composition that can be used indoors and with strict VOC (volatile organic compounds) requirements since there are no VOC used in this paint
• Repels liquid droplets that pick up contaminants such as dust, dirt, and air pollution, enabling the coated surface to self-clean
• Gives surfaces contact angles greater than 150°, preventing water, oil, and all other liquids from seeping into the painted or coated surface
• Enables production of superhydrophobic, superoleophobic, and omniphobic paints and coatings, benefitting many industries

Technology

In these composite particles, the combination of two features, hydrophilicity at the core and hydrophobicity on the outside, makes the particles both dispersible in water and able to leave a superhydrophobic, superoleophobic, or omniphobic coating on a surface on drying. The hydrophilic core particle has smaller, silicone-based hydrophobic particles bonded around it. The composite particles can disperse in water-based paints or coatings under certain conditions, and upon application to a surface and drying, can coat surfaces, making them superhydrophobic, superoleophobic, or omniphobic. The surface is highly hydrophobic and difficult to wet, having a water droplet contact angle greater than 150° and roll off angle less than 2°. The surface is also highly oleophobic, difficult to wet with oil, and highly omniphobic, difficult for solids to stick to the surface.