This hair-thin carbon fiber moves on its own when voltage is applied

Researchers from the Polish Academy of Sciences have demonstrated that hair-thin, uncoated carbon fibers can bend and straighten on command when voltage pulses are applied, without any direct wiring. Using a closed bipolar electrochemical cell, the team exploited the natural surface roughness and asymmetry of certain carbon fibers to induce uneven ion insertion during redox reactions in an ionic solution. This uneven ion distribution created differential tension across the fiber, causing it to act like microscopic tweezers that move reversibly and wirelessly in response to applied voltage. This approach overcomes longstanding challenges in creating smart micro- and nanofibers, which typically require complex coatings or modifications to respond to stimuli. By using pristine carbon fibers and a simple electrochemical setup, the researchers achieved precise, reversible, and wireless actuation at the microscale. This breakthrough could simplify the design of micro-scale devices and advance fields such as micromechanics and soft robotics by providing a new, cost-effective method for controlled motion of tiny fibers without complex