If there is a filter medium that can be electronically “switched” to capture particles of different sizes, this is certainly convenient. It turns out that newly developed conductive polymers that change the state will soon be available on demand. The material, which usually exists in solid form, was created by scientists at the University of Linxueping in Sweden and scientists at Imperial College London.
When a positive electrical pulse of only 0.8 volts is applied, it increases in volume by 120 times, absorbing the surrounding water into a gel – a repeating pulse that causes it to expand further. However, once a negative pulse of -0.8 volts is subsequently applied, it will revert to solid state. This allows you to switch back and forth between states.
In laboratory tests, the researchers found that when the material changed, the hole size in the “smart sponge” filter made of polymer soured by 85 percent, allowing for many possible applications.
Professor Magnus Berggren, of the University of Linxueping, said: “The properties of this smart filter can be changed dynamically to allow particles of different types or sizes to pass through. This function can be used for screening, filtration, purification and process chemistry. It can also be used in medicine and biochemistry. “
Scientists Johannes Gladisch and Eleni Stavrinidou led the study, which was recently published in the journal Advanced Science.