Designing the Death of a Plastic
Decades ago, synthetic polymers became popular because they were cheap and durable. Now, scientists are creating material that self-destructs or breaks down for reuse on command.
The environmental effects of plastic buildup and the declining popularity of plastics have helped to spur chemists on a quest to make new materials with two conflicting requirements: They must be durable, but degradable on command. In short, scientists are in search of polymers or plastics with a built-in self-destruct mechanism.
While not a silver bullet for the problem of plastic waste, self-destructing plastics could also enable new applications in drug delivery, self-healing materials and even some electronics.
The starting point requires picking polymers that are inherently unstable, and often historically overlooked because of their fragility. Given a choice, their units would rather stay as small molecules. What scientists do is force those molecules to link up into long chains, and then trap the resulting polymers.
Dismantling these polymers is sometimes called unzipping them, because once the polymers encounter a trigger that removes those traps, their units fall off one after another until the polymers have completely switched back to small molecules.
“As soon as you start the process,” explains Jeffrey Moore, Dr. Feinberg’s supervisor at the University of Illinois, “they just keep going.”