More than 200 years after the dawn of the Industrial Revolution, innovation continues to drive manufacturing gains. One area rich with developments is heat-dissipating materials. In our increasingly computerized world, having materials that can effectively dissipate heat allows smaller, thinner, faster and lighter devices. Researchers at two universities are at work developing materials that can help.
At the University of Michigan, an engineering team developed a method to make a polymer about six times better at dissipating heat than the same material in its untreated state. The method involves dissolving the polymer in water and adding electrolytes to raise the pH, making the solution alkaline. The monomers in the polymer chain take on a negative charge and are repelled from one another. As they spread apart, say the researchers, the polymer chain’s tight coils unfurl. The polymer and water solution then is spin casted into a solid plastic sheets.
Unfurling and recasting the molecular chains provides two benefits, say the researchers. First, the less tightly coiled chains conduct heat more effectively. Second, the polymer chains pack together more closely, making them more thermally conductive.
At Johns Hopkins University, researchers are pursuing materials to replace silicone in microelectromechanical systems (MEMS). Though silicone is the material of choice currently, when exposed to temperatures of a few hundred degrees, the material loses strength and the ability to conduct electrical signals. The John Hopkins team hopes to identify materials with greater strength, density and electrical and thermal conductivity as well as those capable of holding their shape at the microscopic scale.
Working to develop films thinner than the width of a human hair, the researchers identified nickel, paired with molybdenum and tungsten, as a leading contender for a MEMS material with good tensile strength and the ability to withstand high temperatures.