New technique to create adaptive materials

Scientists have developed a technique that causes a composite material to become stiffer and stronger on-demand when exposed to ultraviolet light.

This on-demand control of composite behaviour could enable a variety of new capabilities for future army rotorcraft design, performance and maintenance, researchers at the US Army Research Laboratory and the University of Maryland said.

"The enhanced mechanical properties with potentially low weight penalties, enabled by the new technique, could lead to nanocomposite based structures that would enable rotorcraft concepts that we cannot build today," said Frank Gardea, a research engineer at ARL.

The research, published in the journal Advanced Materials Interfaces, shows that these composite materials could become 93 per cent stiffer and 35 per cent stronger after a five minute exposure to ultraviolet light.

The technique consists of attaching ultraviolet light reactive molecules to reinforcing agents like carbon nanotubes.

These reactive reinforcing agents are then embedded in a polymer.

Upon ultraviolet light exposure, a chemical reaction occurs such that the interaction between the reinforcing agents and the polymer increases, thus making the material stiffer and stronger.

The researchers said the chemistry is generally applicable to a variety of reinforcement/polymer combinations thereby expanding the utility of this control method to a wide range of material systems.

"This research shows that it is possible to control the overall material property of these nanocomposites through molecular engineering at the interface between the composite components.

"This is not only important for fundamental science but also for the optimisation of structural component response," said Zhongjie Huang, a postdoctoral research fellow at the University of Maryland.