4/6/15 SubMicrospheres Team

Vilas Pol, an associate professor in the department of chemical engineering, stands with his lab group where they work to increase the efficiency of submicron carbon spheres.

Purdue researchers are working on enhancing fuel economy with a new efficient method of producing engine lubricants.

Submicron carbon spheres, which are 200 to 500 nanometers in diameter and perfectly smooth in nature, have been shown to reduce surface roughness of materials. According to the American Chemical Society research report published by Purdue researchers, when the spheres are used as an oil additive in engines, the mixture reduces friction and wear by a substantial 10 to 25 percent as compared to neat oil without changing the solution’s viscosity.

Although this technology has been around for a couple of years, a team of Purdue researchers recently discovered a new technique that synthesizes these submicron carbon spheres at a much faster rate, up to hundreds of times faster than was possible in the past. With the production speed of these spheres significantly shorter, the implications of this technology to the fuel and machine economy are boundless, once perfected.

“This research is the marriage between two groups: chemical engineering and mechanical engineering,” said Vilas Pol, research team leader and associate professor of chemical engineering and materials engineering (courtesy).

According to Pol, the precursor method of producing those spheres is to simply put all the chemical materials together and stir it until the sphere is formed, a process that can take up to 24 hours. However, the research team discovered that bombarding the chemicals with ultrasound during their radical polymerization catalyzes the reaction, reducing the time it takes for the sphere’s formation to as little as five minutes.

Abdullah Alazemi, research assistant and graduate student in mechanical engineering, said there have been a few companies interested in using the carbon spheres as oil additives, and they intend to implement the team’s production technique. However, he also said that it is too early to accurately say whether or not this technology will come to realization as there are many other variables that are accountable.

“(The sphere) has been tested (on) surfaces in contact (with each other) for friction and wear, but has not been implemented (in) real engines,” Alazemi said.

Another complication arises since the carbon sphere-oil mixture is not a perfect homogenous mixture but a colloid — tiny particles suspended in a solution due to their light weight. According to Pol, the spheres will remain suspended for three or so weeks until the weight of gravity causes it to eventually settle down. Smaller spheres do have a longer suspension time, and attempts to control the variation of the diameters of the spheres is an ongoing research project for the team. Because roughness of materials vary, being able to confine the spheres to a specific diameter to cater to specific materials is also very crucial for the technology’s success if the team expects to see extensive application.

Pol said, “Sometimes surfaces can be very rough, where the bigger size could be the good thing to use; but, sometimes surfaces could be smooth—high-quality materials could be very smooth—but still could have tiny roughness, where the small particles could do better than the bigger ones.”

The team has found that varying the ratio of the solvent mixture has a direct impact on the diameters. The team will be exploring other methods to control sphere size and may report its findings in the next few months or so.

According to Pol, how soon this technology sees real implementation will depend upon its perfection and the interests of the industry.

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