Multiscale Stress Transmission Regulation toward Flexible Strain Sensors with High Stability

Abstract Flexible strain sensors, characterized by lightweight, thin, and pliable characteristics as well as strain sensing capability, are essential sensing elements in wearable smart devices. Traditional flexible strain sensors are subjected to dynamic imbalance between migration and reconstruction rates of polymer chains, insufficient interfacial bonding strength, and disorganization of stress transmission pathways, resulting in low stress transfer efficiency to ultimately affect device stability. Consequently, achieving efficient stress transmission has remained persistent challenges within strain sensing domain. Here the regulatory methodologies are summarized for multiscale stress transmission across molecular, mesoscopic, and macroscopic levels to develop highly stable flexible strain sensors. These approaches encompass the molecular structural design of polymer materials, optimization of interfacial crosslinking ways, and multilayer structure design. The mechanism influencing chain dynamics, regulatory principles of interface bonding strength and stress field distribution, and stability enhancement mechanism are comprehensively elaborated. The primary objectives focus on establishing efficient stress transmission channels for enhancing the overall stress transfer efficiency, thereby providing universal solutions for stability improvement. Furthermore, specific application cases from single to multimodal perception, ultimately to system functional integration are categorized. The critical scientific issues and challenges of multiscale regulation are discussed, providing theoretical insights for developing high‐performance flexible strain sensors.