Force-indicating smart adhesives enabled by mechanochromic elastomer

Adhesives are essential for binding materials and ensuring the integrity of structural systems. However, adhesive joints often experience force accumulation, leading to potential failure, which remains challenging to monitor in real-time. In this study, we introduce a simple, cost-effective, and versatile strategy for fabricating force-indicating smart adhesives (FISAs) using commercially available materials, including polyacrylate matrices and silicone microspheres as fillers. These adhesives exhibit a pronounced mechanochromic response, driven by reversible cavitation within the elastomer matrix, enabling both qualitative and quantitative visualization of stress distribution at adhesive joints. This capability allows for early detection of adhesive failure, offering a proactive warning mechanism. The adhesive properties, including force sensitivity, are highly tunable by adjusting the polyacrylate matrix composition, microsphere content, size, and interfacial strength, making these FISAs adaptable to a wide range of substrates. This work represents a significant advancement in smart adhesive technology, combining enhanced monitoring capabilities with broad applicability across diverse scenarios.