Mechanical Behavior and Piezoelectric Potential of 3D-Printed Bouligand Structures with Rochelle Salt

Abstract Bioinspired architectures offer an effective strategy for enhancing the mechanical and functional properties of composite materials. In this study, 3D-printed Bouligand structures were designed and fabricated to investigate the correlation between hierarchical geometry, mechanical behavior, and piezoelectric potential when integrated with Rochelle Salt (RS) crystals. The Bouligand scaffolds, composed of helicoidally stacked lamellae with interlayer rotation angles of 4°, 14°, 22°, and 30°, were printed using a resin-based additive manufacturing process and subsequently infused with RS crystals grown in situ for 24 h from a saturated aqueous solution. Mechanical testing was conducted using uniaxial compression and three-point bending to evaluate the effect of layer rotation. The 22° configuration exhibited an optimal balance between stiffness and energy absorption, achieving an average compressive strength of ∼300 N and bending load of ∼100 N, together with enhanced fracture toughness due to efficient stress redistribution and crack deflection. After RS crystal growth, all reinforced samples showed a 20-35% increase in stiffness and improved interfacial cohesion, confirming the reinforcing effect of the crystalline phase. Piezoelectric measurements revealed that the 4° structure generated the highest voltage output (∼0.41 V), attributed to more direct stress transfer to the RS domains, while larger rotation angles led to lower output but superior mechanical resilience. These findings highlight a tunable trade-off between mechanical toughness and piezoelectric efficiency governed by the helicoidal rotation.