Did you know that water doesn’t conduct electricity?   Really, pure water does not conduct electricity.  Rather, the elements and imperfections within the water (such as salt content) break up into positively and negatively charged ions that work to form the closed circuit necessary for conductivity.  Paint is the same: in and of itself, it is not conductive.

Furthermore, did you know that color is a the result of what part of the spectrum is reflected off of a surface?  So a red car isn’t the color red at all – it’s every color EXCEPT red, since that’s the color that reflects off of it.  In this installment of the Chemistry Corner we will be examining some new advancements in color changing paint that rely on electrical conductivity and viewing angle, the applications of these types of paints, and the products available for professional painters to test, measure, and evaluate them.

Inspecting color changing paint in a laboratory. Image Courtesy of BYK

As we’ve discussed before, color changing paint has a lot of uses.  From helping workers at a refinery know which pipes are hot to helping a new mother know that her baby’s milk bottle has cooled to a safe temperature, color changing paint helps lend useful function to many objects.  But temperature is far from the only catalyst in changing the color of paint.  New forms of paint are creating innovative color changing technology that rely on electricity and viewing angle.  The video below shows a new system wherein the paint on a car can be manipulated to change color by the driver adjusting the current flowing through the coating.

Here is an example of a vehicle that changes color based on viewing angle.

So how do these technologies work?  How do paints change color based on the electricity passing through the coating or the angle the viewer stands in relation to the object?  Science!

More specifically, they work by manipulating the chemical elements of the paint.  Cars that change color due to electrical current, a process known as chromism, are doing so based on the change of electrons in the paint due to exposure to different levels of electrical current.  Some of the elements in the paint are temporarily rearranged and the electrical stimulation of the electrons cause them to change shade or hue.  Once the current is reduced or reversed back to its prior level, the electrons change back to the their original state and thus appear to be the original color.

Paint that changes due to viewing angle does so by having tiny glass-like flakes mixed in with the original paint.  The flakes work like millions of tiny prisms within the paint, interfering with both the reflection and refraction of the light that is shined on the coating.

Split Screen Example of a vehicle with paint that changes color due to electrical current. Image courtesy of FQuick.com

Achieving high level results when painting with these types of materials can be a challenge.  Unlike a standard coating which can be measured with drawdown cards and standard color analysis instruments, color changing paint can only be measured with specific devices that are calibrated to recognize the function of the paint itself.  For example, BYK produces a number of different spectrophotometers designed to measure and control effect finishes like the ones mentioned here.

So why is it important to properly measure color changing paint?  Simple: because of the very nature of the paint changing color due to outside catalysts, there is a need to make sure the non-stimulated color of the paint is correct after curing.  Having the steady state paint color measured correctly means that any change due to viewing angle or electrical current is properly calibrated as well.  Click here to view some of the other measurement instruments offered by BYK to make sure you are using the right paint for the job – color measurement doesn’t have to be complicated but you have to use the right tools!