Ars has an interesting piece today about a self-healing polymer that could be used to create scratch-resistant iPhones.
In today’s issue of Science, Biswajit Ghosh and Marek Urban from the University of Southern Mississippi present a new polymer design that can employ UV light from the Sun to activate a latent self-pair capacity. Their strategy involves using the combined functions of three chemical components.
At the core of their design is polyurethane, which is an elastic polymer that already has decent scratch resistance. To enhance its ability to withstand mechanical damage, Ghosh and Urban added two more components, OXE and CHI. OXE has an unstable chemical structure (a four-membered ring containing three carbons and one oxygen) that makes it prone to being split open. CHI is UV sensitive.
The idea is that, if the polyurethane gets damaged by a scratch, the unstable ring structure of OXE will open to create two reactive ends. Then, UV light can trigger CHI to form new links with the reactive ends of OXE and thereby fix the break in the polymer.
Ghosh and Urban purposefully created scratches in films of their polyurethane-CHI-OXE material and tested to see if it mended itself under UV light. When they placed the damaged film under a 120 W fluorescent UV lamp, the scratches became negligible within half an hour. This repair reaction can work under a variety of conditions, ranging from dry air to high humidity.
They estimated that the UV lamps used in the experiments generated about a 0.3 W/m2 per nm power density, which is only a little more than what the Sun gives off on average (0.25 W/m2 per nm). Thus, they propose that the repair would take about the same amount of time under sunlight. Of course, the time of the year would matter—the process could take much less time under the harsh summer sun or much longer on a gloomy winter day.
The ability to use natural sunlight for self-repair and the simple design are advantageous, but this polymer system still needs some work before it can be released commercially. For example, the authors must figure out what happens if a second scratch occurs directly where a previous scratch was mended. They also need to determine the shelf life of their three-component polymer.
Mending scratches on pretty tech with the power of sunlight – can it later be employed for greater damage like cracks, breaks and battlestars? Cool stuff, right up there with self-cleaning socks.
I’m Community Manager and Admin for the NewsBoiler Network, home to N4G, TechSpy, AnimeShinbun, FilmWatch and 11×2. I also write for network editorial site, ZTGD.
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