Breakthrough in Conducting Polymers: Polyaniline's Perfect Diamagnetism

**Researchers from the University of Tsukuba have made a remarkable breakthrough in the field of conducting polymers by synthesizing polyaniline with perfect diamagnetism,** a property typically associated with superconductors. This discovery is significant because conducting polymers generally exhibit paramagnetism, where they are weakly attracted to magnetic fields. **Diamagnetism, on the other hand, completely repels external magnetic fields, which is the opposite behavior.** The study involved the synthesis of polyaniline in the presence of iron sulfate, which led to this unique property. **Superconducting Quantum Interference Device measurements confirmed that the magnetic susceptibility of the synthesized polyaniline experienced a gradual negative shift from around 100 K, showcasing perfect antiferromagnetism below 24 K.** Typically, conducting polymers show significant variation in electrical conductivity and resistance with changes in temperature. However, the polyaniline in this study demonstrated minimal change in electrical resistance across temperatures, with only a significant reduction in conductivity at very low temperatures. This discovery of perfect diamagnetism in polyaniline may be due to an unconventional underlying mechanism, **suggesting a potential new frontier in the development and application of conducting materials.** Such a breakthrough could lead to advancements in fields utilizing conductive polymers, including light-emitting devices, electromagnetic shielding, and more. The research was supported by the Japan Society for the Promotion of Science, indicating its significance and potentiality for future innovations.