Products containing thermochromic pigments change color—sometimes permanently—due to heat exposure. Could these pigments raise awareness of the dangers caused by above-average temperatures? Since that warmth can cause everything from food spoilage to burns, individuals have explored how to rely on these pigments as visual safety indicators. Knowing the basics of how they work could help you decide whether or not to use them.

When someone notices a substantial color change in an item containing thermochromic pigments, that’s their cue to explore what happened, and why. That includes doing whatever is necessary to protect people from potential harm, or teach them to look for the color change and understand its meaning.

Supporting Food Safety with Thermochromic Pigment

Most consumers know to discard food if it has a strange smell, taste or texture. However, people can usually only assess those things after bringing products home from the store and eating or cooking with them. What if people could quickly check a perishable product’s package and see if it may have gotten too warm?

A 2022 academic review of thermochromic pigment on cold food packaging shows people have tried various options. For example, reversible thermochromic pigment fluctuates as an item’s temperature changes. The most common types add rich color to products containing them. However, the color becomes translucent or disappears due to heat exposure.

There are also irreversible thermochromic pigments, which permanently show a color once something gets too warm. People could quickly check for that hue on the packaging before buying any food subject to spoilage. Even if a perishable product got too warm on a truck a few days ago, irreversible pigments could continue displaying the evidence of that event until someone notices the problem and throws the item away.

If grocery store personnel and consumers know to watch for the colors, that awareness should significantly reduce potential instances of food poisoning and customer dissatisfaction. Some packaging manufacturers have designed products so thermochromic pigments appear in specific parts, such as within small windows on the front. Then, it’s easier to know where to look, especially if the package has an instructional prompt, such as: “Check for freshness here.”

The academic review also clarified how thermochromic inks can support food safety by warning people a just-heated product is still too hot to handle without people risking significant burns. Reversible thermochromic inks are most appropriate in such cases because they’ll appear one way after someone heats the product and then gradually look different as it cools.

Reducing the Dangers of Heat-Related Illness in Older People

Numerous studies indicate people become less able to recognize extreme heat and its effects as they age. That effect can happen even in healthy older people but is especially problematic in adults with cognitive decline. 

Similarly, as people age, some are less likely to know when their bodies are too cold. When individuals hear about cold-related injuries such as frostbite, many automatically assume they happened to stranded hikers, skiers who’ve spent hours on the slopes without breaks, or others subjected to outdoor temperature extremes. However, people are in their homes when experiencing about 20% of cold-related injuries. Relatedly, older adults face hypothermia risks when experiencing relatively mild, cooler temperatures, such as 60-65 ˚F.

A 2021 study of adults in the United Kingdom found many ignored extreme heat warnings. The work examined people’s responses to heat that could be dangerous for vulnerable individuals. The results showed only 25% of potentially vulnerable adults behaved differently after hearing extreme heat alerts. Additionally, respondents were often more concerned about sunburn than other high-temperature risks. However, heat exposure can result in complications such as seizures or loss of consciousness.

The researchers concluded the current messaging is not working well enough, especially because many older adults did not realize extreme temperatures may affect them. How could thermochromic pigments help people recognize changing temperatures faster?

Developing a Color-Changing House Paint

What if someone could use the color of their house as a guide to temperature changes that could threaten their safety? It might sound far-fetched, but recent work reveals the possibilities. When viewed with a microscope, thermochromic pigments appear as encapsulated molecules that only develop water resistance when combined with that liquid. People can then add binders to create pigmented products that meet their performance requirements.

In one 2023 case, researchers took inspiration from a chameleon native to Africa when using thermochromic technology to create a house paint that changes its color as the outdoor temperature fluctuates. The group mixed thermochromic microcapsules, specialized microparticles, and binders to create a substance suitable for brushing or spraying onto a surface.

Similar work in this area includes paint that keeps buildings cooler or warmer, but they usually can’t switch between states as the environment changes. This paint was different, it began changing to a lighter shade of grey at temperatures beyond 68 ˚F and shifted back once the area cooled. Additionally, the film treated with this coating reflected up to 93% of the sun’s radiation. However, it could also keep a home warmer.

Experiments also showed the pigmented coating did well during autumn and spring days when the outside temperature fluctuated so much that a home’s occupants might need both the coating’s heating and cooling capabilities in a single day.  Considering how extreme temperatures affect some people more than others—and often before they realize it—thermochromic pigment applications such as this one could give people visual indicators of changing temperatures, while offering practical mitigations.

Supplementing Existing Equipment Maintenance Plans

Equipment technicians must adopt problem-solving mindsets and interpret what they can see, smell, or feel when assessing a company’s industrial assets. However, paint infused with thermochromic pigments could show them another sign of trouble, ensuring they don’t overlook it.

Some types of thermochromic paint monitor surface temperatures, giving people better visibility of their mechanical and electrical assets. One commercially available product changes color five to 20 seconds after an item crosses a defined temperature threshold. The full transition occurs within approximately 60 seconds.

People can use this product and others like it to recognize issues, even without specialized training on how to fix or diagnose problems with a piece of equipment. Connected sensors and their associated dashboards allow people to monitor assets ranging from fleet vehicles to industrial boilers. That’s helpful, but it’s also valuable when on-site team members can recognize abnormalities without technical backgrounds.

Imagine if an industrial asset treated with thermochromic paint had a sign posted next to it instructing people to contact someone immediately if the painted area turns a specific color. That approach allows anyone to assist by knowing what to look for and how to report a suspected problem.

It can also streamline the time between identifying a problem and having it fixed. Since the paint shows abnormally high temperatures, people can quickly source a technician to investigate further. The alternative often means specialists initially identify issues during annual servicing appointments and those people may need advanced equipment to detect such problems.

Incorporate Thermochromic Pigment into Safety Plans

Beyond the examples given here, people have explored applying thermochromic pigments to products such as welding gloves, car exteriors, and even infant clothes that detect possible fevers. Most learn from very young ages that excessive heat can pose safety risks, whether associated with a hot stove or paved surfaces at their favorite playgrounds.

As individuals progress through life, they remain aware of temperature-related safety concerns. Maintaining that understanding is particularly important for those working around equipment that can get extremely hot and require protective measures. People should strongly consider using thermochromic pigments, along with other appropriate safety measures. Products with such ingredients provide easily understandable signals of heat-related dangers, making them highly applicable to various industrial and household settings.