Advanced nanocomposites for 4D printing: High-performance electroactive shape memory polymers for smart applications

• Enhanced Electrothermal Response – PLA/ MWCNT composites achieve 80 °C in 10s. • High Shape Recovery – Optimized SMPs show 98.56 % recovery and 99.6 % fixity. • Soft Robotics Application – 3D-printed robotic hand mimics human motion precisely. • Validated Simulation Model – Numerical results align closely with experiments. The potential of 4D printing to enable dynamic, programmable structures has been constrained by the reliance on heat and moisture as activation stimuli, limiting the complexity of shape transformations and hindering localized actuation. This study addresses these limitations by developing electroactive shape memory polymers (SMPs) by incorporating multi-walled carbon nanotubes (MWCNTs) into poly(lactic acid)/polyvinylidene fluoride (PLA/PVDF) blends. Using fused deposition modeling (FDM)-based 4D printing, the MWCNTs were strategically dispersed within the polymer matrix to enhance both electrothermal responsiveness and mechanical properties. The optimized composite, containing 7.5 % MWCNTs, achieved a rapid temperature rise to 80 °C in just 10 s under a low voltage, alongside outstanding shape recovery and fixity ratios of 98.56 % and 99.6 %, respectively. Numerical simulations developed in Abaqus accurately replicated the electrothermal behavior and shape recovery dynamics, with results aligning closely with experimental observations. The advanced SMPs were successfully implemented in bio-inspired origami structures and soft robotic hands, showcasing precise actuation, high flexibility, and robust structural integrity. These findings reveal the transformative potential of electroresponsive nanocomposites for next-generation applications in soft robotics, bio-inspired mechanisms, and adaptive intelligent systems.