It is not a simple task to sort out the many delicate fragments that make up modern electronic equipment, but if we want to recycle them, this is something we must face . In reality, the inherent difficulties of this process cause millions of tons of e-waste each year, but new research shows how we can solve this problem by dissolving key components in water.

This research was carried out by scientists at Tianjin University, who previously developed a new type of zinc-based nanocomposite material that is soluble in water. Their idea is that this material can be used in temporary electronic circuits, but the team found that its conductivity is not enough to be used in consumer devices.

To solve this defect, the team modified the zinc-based nanocomposite by adding silver nanowires, which in turn made it highly conductive. This mixture is then screen printed on a degradable polymer called polyvinyl alcohol, and the circuit is cured by a chemical reaction initiated by water droplets.

This forms a nanocomposite circuit board, which is then mounted in a shell made of more polyvinyl alcohol, and at the same time, it is added to measure the human heart rate and blood oxygen. Level and step number sensors complete the smart watch design. In the test, the prototype of the wearable device reached an optimal state in enduring sweat, but it could not “survive” in water.

When the entire device is completely immersed in water, the polymer housing and circuit will be completely dissolved within 40 hours. What is left is the OLED screen and its microcontroller, as well as the resistors and capacitors incorporated into the circuit for recycling. The prototype is still some distance away from the smart watches you see on the wrists of wearable device enthusiasts, but scientists believe they have laid the foundation for building similar devices.