In 2009, a chance discovery at Oregon State University led to the discovery of a brilliant blue pigment in the lab of professor Mas Subramanian.
The new blue, created through the superheating of a manganese compound, had a crystalline structure so stable, it could resist heat and acid. Bonus: It was environmentally benign and relatively cheap to produce from a readily available mineral. The discovery was heralded in science publications around the world and made The New York Times.
Since then, Subramanian and his research team of professors and chemistry students have used the same process to create new colors, including a brilliant orange pigment — fitting for OSU’s signature color. They’ve also developed new shades of blue, green, brown, yellow, turquoise and aquamarine.
“It was serendipity, actually; an accident of discovery,” Subramanian said of the initial discovery, as he worked with his team in a lab in Gilbert Hall on Thursday.
Two years ago, Subramanian was exploring the electronic properties of manganese oxides, when a former graduate student, Andrew Smith, pulled a sample out of a furnace that had been heated to nearly 2,000 degrees Fahrenheit. When Subramanian saw the brilliant blue that the compound had turned, he recognized that something amazing had happened.
He quickly changed the focus of his research.
The new compound had properties affecting the absorption of light. That consequently affected its color. As a scientist might describe it, the new pigments share an unusual “trigonal-bypyramidal coordination” crystalline structure, with atoms that are combined in a certain five-part coordinated network. Once they understood the chemistry behind the crystalline structure, they were able to slightly modify its elemental ingredients, Subramanian said.
For instance, manganese resulted in brighter blues. Iron enhanced orange. Copper and titanium together created vibrant greens.
Only deep reds have eluded the lab.
“Red is the most difficult to make in inorganic pigments,” Subramanian said Thursday. Many red pigments are now made with cadmium and mercury, which can be toxic.
That’s part of the reason why the new pigment colors that have been created so far are special.
For instance, the blue pigment has properties that have eluded humans for thousands of years, dating back to the Han dynasty in China, ancient Egyptians and Mayan culture. Most previous blue pigments had various problems with toxicity.Some are carcinogenic, others emit toxic gases.
OSU already has applied for a patent on this technology. Private industry is testing samples, and the latest findings were published in a May 31 article in the journal Inorganic Chemistry. The co-authors were Peng Jiang, Jun Li and Arthur W. Sleight.
The beauty of the new pigments lies not just in their vibrant colors, but their durability. The compounds are extremely stable, meaning that they do not fade — even if left in an acid bath for hours on end. The pigments are also stable in oils and water, creating significant potential in the paint and pigment industries and beyond.
For instance, roofs painted with these pigments can help cool buildings because they reflect most infrared light. So, the ability to make blue roofing materials that never fade could play a part in the sustainable building materials industry.
Although the pigments have not yet been sold commercially, a few artists have used samples of the blue in their artwork, including Subramanian’s wife, Rajeevi, an oil painter. In addition, museums are interested in the stable colors to safely restore art masterpieces without corroding the original colors beneath.
“The basic crystal structure we’re using for these pigments was known before, but no one had ever considered using it for any commercial purpose, including pigments,” Subramanian said. “These should all be very attractive for commercial use.”
Next, the research team will dive deeper into initial experiments to combine two or more elements to see if they can create new colors by "mixing" at the chemical composition level.
Experience and hardwork
Subramanian is the Milton Harris Professor of Materials Science at Oregon State University. He has been at OSU for five years, following a 22 year career with Dupont. During his career, he has developed more than 60 patents and authored or co-authored more than 300 scientific papers.
“That kind of experience helps," he said. "Luck favors alert minds … Many times you will find something more amazing than what you are looking for."
In all, Subramanian has eight doctoral candidates, three post-doctorate fellows and three undergraduate chemistry majors working under him in the lab. Several of the students came to OSU, over programs at schools such as Cornell University and University of California at Davis to work with Subramanian.
The lab works long hours, typically 12-hour days. Subramanian's students are also researching the possibility of using thermoelectrics in small systems — for instance, an automobile - to efficiently generate electricity waste heat.
A universal topic
Subramanian said he never imagined that he would work in a area of chemistry research that captures the excitement of so many people outside the field.
The process is difficult to explain in simple terms, but lay people can grasp the importance and significance of creating a new color. People are amazed, he said.
"I'll get some crazy calls," Subramanian laughed. Everything from people who want to paint their house with a color that never fads or requesting that he name one of the new colors after their child or perhaps name one "Kind of Blue" in honor of jazz musician Miles Davis.
For now, the lab has dubbed the various shades of blue "Mas blues" in honor of their chief researcher, but the new pigment colors do not have official names.
The research is supported by grants from the National Science Foundation, Department of Energy, Oregon Nanoscience and Microtechnologies Institute and the U.S. Army.
Andrew Smith, the graduate student who was there for the initial discovery in 2009, has since graduated and now works for the international Shepherd Color Company, which is one of the companies working to commercialize the new pigments.
OSU News and Research Communications writer David Stauth contributed to this report.
Contact business reporter Nancy Raskauskas at email@example.com or 541-758-9542. Follow her on Twitter @NancyR10.