EurekAlert October 29, 2019
Materials, such as solids and gels, that change volume depending on temperature or pH have long been available. An international team of researchers (Sweden, UK) placed a conducting polymer with a thickness of a few micrometres around an electrically conducting carbon fibre. When electrical pulses with magnitudes of +0.5 V or +0.8 V are applied, the material changes its internal structure, then absorbs water and is finally converted to a gel that expands to 14 or 120 times the original volume. When pulses of magnitude +/- 0.5 V are repeatedly applied, the material expands by approximately 300%, with respect to its previous contracted state. The change in volume is reversible. It has application in smart sponge, or filter, in which they can control the expansion electronically, and in this way change the pore size by 85%. The properties of this smart filter can be dynamically changed to allow different types or different sizes of particle to pass through. This function can be used for sieving, filtration, purification, and in process chemistry. It may also have applications in medicine and biochemistry…read more. Open Access TECHNICAL ARTICLE
LQCM‐D characterization of the polymer volume changes. Frequency and dissipation response to electrochemical switching in 0.01 m KCl (ΔFn/n and ΔDn/n). Credit: Advanced Science, 28 October 2019