Low‐Temperature Imidization of Polyimides (PI) for Scalable Manufacturing of Flexible Wearable Electronics

Polyimide (PI) is widely used in flexible electronics because of its excellent mechanical and thermal stability; however, its high imidization temperature (>200 °C) is incompatible with low‐cost polymer substrates such as polyethylene terephthalate (PET), limiting scalable roll‐to‐roll manufacturing. The objective of this work is to enable screen printing and low‐temperature curing of PI on PET without compromising mechanical or electrical performance. To achieve this, a polyethylene glycol (PEG)‐modified PI precursor is developed, in which PEG acts as a plasticizer to enhance chain mobility and promote imidization at reduced temperatures. Using this approach, effective imidization is achieved at 140 °C, well below the thermal tolerance of PET, allowing fully screen‐printed fabrication of flexible electrodes without rigid carrier substrates. The printed electrodes demonstrate robust mechanical performance, with stable electrical resistance under cyclic bending and stretching up to 30% strain. Furthermore, the electrodes enable reliable real‐time electrocardiogram and electromyogram signal acquisition, confirming their suitability for wearable biomedical applications. This work establishes a scalable and cost‐effective pathway for integrating PI‐based electronics with low‐temperature polymer substrates, advancing roll‐to‐roll manufacturing of flexible wearable devices.