Acrylic Structural Adhesive Strategies for Enhanced Performance in Hybridized In‐Mold Electronics under Mono‐ and Bidirectional Deformation during Thermoforming

In‐mold electronics (IME) is a technology that combines printed electronics with in‐mold decoration to create conformable functional 3D electronic devices. Structural adhesives play a crucial role in these devices; however, their influence on film deformation during manufacturing can compromise electrical performance. Prior studies have evaluated adhesive amount and placement primarily under uniaxial deformation. However, IME devices may also undergo more complex (bidirectional) deformation, and the effect of adhesive variation under these conditions remains underexplored. This study investigates how variations in structural adhesive quantity and placement influence hybridized film deformation and circuit resistance under both monodirectional and bidirectional deformation during thermoforming. Results show that films with small adhesive drop size and aligned placement to the pad exhibit higher resistance to monodirectional deformations. Conversely, films with larger adhesive drop size placed inversely, show enhanced resistance to bidirectional deformations. These findings advance the current understanding of hybrid electronics design, offering practical strategies for improving reliability and manufacturability of IME systems under diverse mechanical loading conditions.