Iowa State University,
Keywords: coating, additives, hydrophobic coating
Summary:Scientists from Janas Materials Inc. have recently developed a new technology that can make surfaces water-repellent, using tiny particles. These particles are called Janus particles and are made up of two different halves - one half likes water, and the other half doesn't. The geometry mimics the surfactant molecules used for making soap. However, these Janus particles contain millions of soap molecules on the surface, therefore they are much more potent. The research team found that by mixing Janus particles with conventional coatings, these particles created a very thin layer on top of the dried coating surface. This layer is so thin that it is invisible to the naked eye, but it makes the surface water-repellent. Potentially Janus particles could replace the toxic forever chemicals such as PFAS and PFOS, which are commonly used as coating additives. In addition, Janus particles are water-based, they can even help reduce the use of harmful VOC (volatile organic compound) in the coating formulation, which helps make the coating system more environmentally friendly. In a preliminary test, coating films made from Janus particles are also more durable than coating films mixed with conventional water-repellent additives. Because almost all the Janus particles automatically go to the top of the coating surface, they do not negatively impact the bulk properties of the coating materials. On the other hand, conventional water-repellent additives are known to deteriorate coating performance, especially adhesion and durability. This technology is easy to apply. Coating manufacturers do not need to completely reinvent their product lines, as Janus particles can be directly added to the commercial coating formulations. This significantly lower the barrier for industry to adopt the technology. On the other hand, Janus particles are made from emulsion polymerization reactions, which are economic and scalable. This technology has a wide range of potential applications. For example, it could be used to create self-cleaning coatings that repel dirt and dust, making them easier to clean. Combined with other antifouling technologies, Janus particles could be applied as marine coating or protection for wind turbine blades.