PMMA-Assisted Conformal Transfer of High-Precision Circuits for Flexible Devices

High-precision flexible circuits are essential for the miniaturization of flexible sensors. However, limitations in existing flexible circuit manufacturing technologies have restricted their widespread application in physiological signal monitoring. To address these challenges, this study develops a new method for transferring ultrathin flexible circuits with resolutions as fine as 5 μm, enabling conformal attachment onto a wide range of substrates. Transfer precision and compatibility with complex substrates can be significantly enhanced by incorporating auxiliary strategies using poly(methyl methacrylate) (PMMA) overlay films. The circuit-substrate interfacial stability can be further improved by introducing covalent bonding. Based on this, this paper constructs the control unit of the manipulator and a highly sensitive temperature sensor, providing a feasible solution for intelligent prosthetic devices, and realizes real-time monitoring of body temperature through a mobile application. Benefiting from the ultrathin, flexible, bendable, low-cost, corrosion-resistant, and long-term stable characteristics, the transferred circuits exhibit broad application prospects in various fields such as wearable devices, implantable medical systems, embodied intelligence, and human-machine interaction.