UCSD Researchers to Build Self-Sensing, Self-Healing Material

12 December 2003

Researchers at the University of California, San Diego (UCSD) Jacobs School of Engineering have been awarded nearly $1.7 million from the National Science Foundation (NSF) to create a new structural material with embedded sensing capabilities.

Principal investigator and Jacobs School professor Sia Nemat-Nasser will integrate this latest project into his ongoing efforts to create a strong structural material with self-healing and tunable electromagnetic properties.

“We plan to take the concept of a multifunctional material a step further by weaving micro-chips or miniature sensors with on-board data processors and copper wire into a braided, fiber-reinforced polymeric composite,” says Nemat-Nasser. “The embedded sensors could help detect such things as damage, unsafe conditions, the operating environment or other external factors, as well as collect data on the structure’s overall status.”

In ongoing work, Nemat-Nasser has already created a material that exhibits self-healing properties. “This composite material contains a chemically manufactured polymer matrix that can re-polymerize its broken covalent bonds and heal at the molecular level,” explains Nemat-Nasser. The same thin strands of woven copper that link the embedded sensors also provide electrical and thermal conductivity and increase the rate of polymerization as heat circulates through the material. Strong and lightweight Kevlar fibers in the composite are also affected by the rise in temperature, contracting to put pressure on the matrix.

In early laboratory demonstrations, Nemat-Nasser showed that after fracturing the polymer, the material bonds back together. “The material covalently rebonded in a matter of hours, and it continued to polymerize and grow in strength actually getting better with age.”

Nemat-Nasser foresees this multifunctional material being used to increase the safety, performance and functionality of military vehicles, aircraft, buildings and bridges. Nemat-Nasser and his collaborators are in the process of creating the multifunctional material and testing its components, and anticipate the creation of a working prototype in 2004.

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