Professor Jonathan P. Singer from Rutgers University in New Jersey (USA) has developed a technology for coating complex three-dimensional structures over their entire area. It can be used both for simple coloring of products (including those printed on a 3D printer), and for processing them with special substances. The working name of the technology is "electric fog".
As a basis, Professor Singer took the well-known method of electrospray paint, in which the liquid at the exit from the nozzle of a 3D printer is crushed into many drops and passes through an electromagnetic field. The drops receive a charge, and with it the property of being attracted to surfaces, on which they are further retained due to the adhesive properties of the paint itself. The peculiarity of the method is that the stream of drops can be directed at different angles from the nozzle in order to reach the points to which the paint cannot be delivered with a direct stream.
Singer's installation instead of a stream of paint creates a suspension, cloud or fog, which also consists of charged paint particles, only now they fill any three-dimensional volume that they fall into. If it is a lattice multi-level 3D printed structure, the droplets will penetrate deeply into it and settle over the entire available area. They form a polymer film that is strong enough to maintain its shape even when the base itself deforms. This property has been verified by filling and drying a colored hydrogel structure.
Now the professor's team is working on a transition device or a new type of nozzle for conventional 3D printers, so that they can not only print, but also paint objects. At the same time, the development of coatings with different properties is underway - just painting complex structures is not enough, you need to learn how to give them new useful qualities.