Two research groups from Virginia Tech have worked together to develop a technique to measure the internal structure of Nafion and have found ways to change its structure to suit a wide range of applications. The details of the study are published in Nature Materials.
Nafion’s molecules feature non-stick nature and strength of Teflon as well as conductive nature of an acid. A small channel network with nanoscale dimensions transports ions or water rapidly through the polymer. The assistant professor of polymer, physical, and materials chemistry, Madsen stated that scientists were unable to determine the Nafion’s properties with standard analysis instruments, such as transmission electron microscopy owing to its irregular structure.
Researchers could track molecular motion within Nafion using nuclear magnetic resonance (NMR) and could also calculate its molecular alignment by combining X-ray scattering with NMR. A novel feature discovered was local alignment of aggregates of polymer molecules in the material, the arrangement being similar to strands of dry spaghetti placed adjacent to each other in a box. They also found that the preferential direction and speed of water motion could be impacted by the channel alignment.
Madsen stated that the degree of alignment could be varied significantly by stretching the molecules. He added that the molecules travel rapidly along the stretched direction in a predictable manner, and that the materials exhibit some liquid crystals properties. Researchers predict that by studying the direction and movement of Nafion molecules, they can be used for developing new materials. The material can also be used in actuator equipment such as organic batteries, artificial muscles and energy-efficient fuel cells. They could also be used to enhance reverse osmosis membranes for purifying water.
Source: http://www.vtnews.vt.edu/