Researchers at the universities of Massachusetts and Pittsburgh in the US have developed a new technique to repair surfaces using oil-based microcapsules filled with a nanoparticle solution.
Nano capsules
Using a polymer surfactant that stabilizes oil droplets in water, the researchers encapsulated cadmium selenide nanoparticles in nano size thin wall capsules in such a way that the particles could be released when desired. The capsules roll or glide over damaged substrates and selectively deposit their nanoparticle contents into the damaged or cracked regions due to hydrophobic–hydrophobic interactions between a nanoparticle and the cracked surface. The nanoparticles can easily be tracked too because cadmium selenide is fluorescent.
Working
If nanoparticles were held in a certain type of microcapsule, they could probe a surface and release the nanoparticles into certain specific regions of damaged surfaces, where the defective regions possess characteristics that are very different to the undamaged one in terms of topography, wetting properties, roughness and chemical functionality. When applied the microcapsules glide over a surface and go into the cracks or imperfections that they encounter and release their nanoparticle cargo into them to repair them.
Applications
The technique has many practical applications in industry and research by avoiding the need to coat an entire surface when only a small fraction of it has been damaged. It could help massively to lower the amount of material required when repairing a damaged object or sample. It can also be used to detect damaged substrates by depositing sensor material into the regions of concern. It cam be used to repair a wide range of objects from aero plane wings to microelectronic components and biological implants.