Switchable Water-based Paint

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Image is for illustrative purposes only and is licensed with CC BY 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/2.0/ Alkyd paints (also known as oil-based paints) use formulations of mineral spirits and petrochemical-based solvents as the carrier phase (as opposed to water in latex or acrylic paints). Once applied to a surface, the spirits/solvents evaporate and the paint particles, which are dissolved within the carrier phase, precipitate and form a uniform, hard and durable coating with few defects and minimal shrinkage. Unfortunately, these paints are associated with strong odours and issues related to flammability and inhalation/environmental hazards and so certain safety precautions and personal protective equipment are needed when using in industrial settings, which increases the cost of the coating process. Queen’s researchers have developed a paint composition that combines the benefits of both oil and water-based paints. Using paint particles whose solubility in water can be switched on/off with exposure to CO2, the researchers have created a homogeneous water-based paint composition that forms a water insoluble coating upon drying. The paint composition comprises carbonated water and paint particles that are soluble under such conditions. While sealed in the can the paint composition is very much like an alkyd paint, a homogeneous system of dissolved paint particles, but without the issues associated with volatile organic solvents. Upon application to a surface, the carbonated water evaporates and the paint particles switch to their water insoluble form which causes them to precipitate and form a uniform coating, much like an alkyd paint. Because the particles have switched to their water insoluble form they can no longer be dissolved by water and, therefore, are stable.