In order to preserve the original color of the product, the protective coating material must also be transparent and colorless. However, all of these requirements must be met in order to provide self-healing functions. High hardness and excellent durability are among the materials with free molecular movement with remarkably poor self-healing performance.
While the reverse is true for materials with high self-healing efficiency but low durability. Researchers from Korea Research Institute of Chemical Technology (KRICT) led by Dr. Jin Chul Kim, Dr. Young Il Park and Dr. Ji-eun Jeong have created a transparent coating material.
This coating meets all of the above requirements, performs similarly to commercial protective coating materials, and can self-heal using only sunlight (especially sunlight in the near-infrared light, wavelength range in 1,000 to 1,100 nm).
Surface scratches can be repaired using a self-healing protective material developed in 30 minutes when exposed to sunlight. The research team used a spray-coating machine to coat a laboratory-scale model car to demonstrate the self-healing capabilities of the developed coating material.
The scratches completely disappeared and the model car returned to the surface of the coating material as before after spending about 30 minutes in the midday sun. The guiding principle of the self-healing phenomenon The surface temperature of the grown material increases when sunlight is absorbed, as the light energy is converted into thermal energy.
The repeated dissociation and recombination of chemical bonds in the polymer structure are enabled by the elevated surface temperature to self-heal the surface scratches. The research team combines a currently available commercial coating resin with a transparent photothermal dye and a dynamic chemical bond (disrupted urea structure).
It can replicate the decomposition and recombination of the polymer structure, so that the dynamic chemical bonding can occur actively upon exposure to sunlight. Even though photothermal dyes have been used to study self-healing properties, most previous research has focused on inorganic materials, which are challenging to use in industrial settings because the coating material needs to be transparent. .