Men - and women - whose work or daily routines include strenuous physical activity that may lead to some few hits in their bodies, like those in the military or those who do sports, can momentarily tolerate a couple of physical injuries, but in the long run, may be faced with serious illnesses, like those that affect the brain.
Brain damage that may eventually impair the body for the rest of one's life may result from head trauma due to, say, bomb blasts or rough tackles. Currently, such effects on the brain are not immediately detected right at the time of impact.
A team of researchers at the University of Pennsylvania have developed a synthetic material that indicates how great the impact is by changing colors, when it is hit. With this material, the researchers aim to be able to apply the same techniques to headgear that people can actually use to detect obvious and immediate injury.
The researchers will present their study among over 9,000 presentations at the American Chemical Society's (ACS) 250th National Meeting & Exposition.
"If the force was large enough, and you could easily tell that, then you could immediately seek medication," said University of Pennsylvania's Shu Yang, PhD. According to Yang, a patch that is responsive to force and changes color when triggered, will prevent additional injury especially for athletes who continue to do activities that lead to brain damage.
Yang and her team applied holographic lithography (HL) and created photonic crystals with particular colors through carefully designed structures. The idea is that when the crystals are deformed by an applied force, they change structures and therefore, their colors.
Yang said it's expensive to make these color-changing crystals and isn't suitable for mass production, but a finished product does not require any sort of other tools or even power, to do the job of detecting on-site injuries.
To make production cheaper, the team of researchers switched the HL method to self-assembly and polymer-based materials. In the ACS meeting, research fellow Younghyun Cho, PhD will discuss how the material was developed in a way that could open up commercialization.
First, they molded the polymer into a structure similar to the photonic crystals. A mold is made up of mixed differently-sized particles of silica. Crystals then assembled into the desired patterns. They heated the polymer in the mold, allowed it to solidify and then removed the silica to create inversed polymer crystals.
To test the reaction of the crystals to impact, the researchers applied varying amounts of force on the polymers and recorded changes in color. The team said the results were encouraging.
One instance, when color was recorded to have changed due to force, was when they applied 30 mN to the polymer crystals which shifted from red to green. That's as strong as a sedan running at 80 miles per hour and crashing into a brick wall. With 90 mN which has a force similar to a speeding truck also hitting the same wall made the polymer crystals turn purple.
"The film can show the color change depending on how much and how quickly the force is applied," said Cho.
In a few years, the same technique may be applied to soldier and sports helmets which can determine the immediate indicators of injuries from the force of a concussion to even a bomb blast.
