A need for breakthrough functional coatings that help reduce environmental impact

Functional/smart coatings is already a vibrant enough topic to have spawned dozens of R&D projects. What is the next “big thing” for smart coatings?

Thierry Destruhaut: There is a huge demand for smart coatings that can support the transition towards a sustainable economy model. For example, if we look at the mobility and construction industry, there is a need for breakthrough functional coatings that help reduce environmental impact and greenhouse gas emissions.

Regarding mobility, PPG is developing new generation of smart coatings that make electric vehicles (EVs) and autonomous vehicles more efficient and safer. Some examples:

• Low-noise coatings for reducing the interior cabin noise in EVs. Since EVs are four times less noisy than traditional engine vehicles, smart coatings are required to make sure that EV drivers are not hearing the outside ambient noise that is usually covered by the noise of traditional engine;
• Electrochromic coatings that instantly switch color or switch from transparent to opaque simply when a button is pressed;
• Fire-protection coatings that protect the batteries of EV vehicles;
• New generation of heating ink for more energy efficient seat heating systems;
• Coatings that maximise near infrared reflection to improve the detectability of a car by the Radar/Lidar sensors of autonomous vehicles; and
• Easy-to-clean coating technology that allows dirt and water to quickly and easily wash away from sensor lenses and improve driving safety.

For the construction industry, smart coatings should be developed to contribute to improving energy efficiency of buildings. The aim is to reach carbon neutral housing and improve the air quality in the indoor environment. Here’s why: Energy management coatings are key because the largest contributor to CO₂ emission comes from housing heating/cooling. Thus, coatings must contribute to thermal insulation or heat reflection. New insulation materials are developed but also energy reflective coatings that reflect infrared or UV light. PPG is already advanced in this field thanks to its presence in the aerospace coating segment where heat and UV management is already key.

Indoor air cleaning coatings are required to reduce pollutants present in the indoor air. Not only should coatings not emit chemicals, they are also required to have a positive contribution to the indoor air quality. Easy-clean and even antimicrobial coatings are also a focus area in order to improve hygiene and reduce the risks of disease transmission. Smog/outdoor pollution can also be decreased with the use of exterior photocatalytic coatings.

Often, nature serves as a model when it comes to functional coatings. What other functions in nature seem interesting and promising for R&D for novel smart/functional coatings?

Destruhaut: Bio-mimicry was already the foundation of our “eggplant” heat reflecting coatings for aerospace and architecture. Currently, we have a particular focus on learning how to create our resin chemical building blocks from natural renewable resources as opposed to fossil resources. Also, if we can copy and reproduce how plant photosynthesis captures carbon from the air, it could potentially be a great help to limiting global warming.

For what functional coatings do you see a larger demand in the market — the ones with intrinsic or extrinsic functionalities?

Destruhaut: The focus of our R&D teams is for more sustainable coatings. As such, the intrinsic property of extending the service live of the coated object is key. Thus, it is key to keep developing even more durable coatings because that helps making manufactured objects and buildings more sustainable. That said, there is also a societal need to expand the role of coatings from their original protective function and add new smart functionalities that will further support the transition towards a sustainable planet.

Where do you see the biggest challenges when it comes to developing functional/smart coatings? 

Destruhaut: Emerging technologies typically have a higher cost, so it is important that the functional benefit that the coatings provide are fully valued in our customers’ decisions. In that respect, credible performance standards are required to quantify the benefits of smart coatings. For example, life-cycle analysis over the full-service life can be a very useful tool to factor the benefits of a green smart coating. But other performance standards are also key to demonstrate the new functional benefits of coatings and convince customers of their value.

Finally, there are some still some gaps in the science that have yet to be resolved. For example, we read a lot in the press about coatings that can produce electricity or that can capture carbon from the air, but we believe that in those cases it will take quite some time before science progresses for that to become feasible.