4D Printing of Polyethylene Glycol‐Grafted Carbon Nanotube‐Reinforced Polyvinyl Chloride–Polycaprolactone Composites for Enhanced Shape Recovery and Thermomechanical Performance

4D printing with carbon nanotube (CNT)‐reinforced polymers enables advanced shape‐changing materials but faces challenges in CNT dispersion and performance. This study addresses these limitations by functionalizing CNTs with polyethylene glycol (PEG), significantly enhancing dispersion and interfacial bonding within biocompatible polyvinyl chloride (PVC)‐polycaprolactone (PCL) composites. The composites, tailored for biomedical applications with a glass transition temperature (T g ) of 37–41 °C, exhibit enhanced mechanical, thermal, and shape‐memory properties. At 0.5 wt% CNT, the composite achieves a 25% increase in tensile strength, 95.78% shape fixity, and a 5‐s recovery time, offering an optimal balance of strength, flexibility, and rapid shape recovery. Higher CNT concentrations (5 wt%) further improve thermal stability, increasing the decomposition temperature by 20 °C and storage modulus by 670 MPa, although ductility is reduced. PEG grafting prevents CNT agglomeration, enabling high filler loading without compromising printability, as confirmed through uniform nanoparticle dispersion and defect‐free fused deposition modeling (FDM)‐printed structures. These intelligent composites combine biocompatibility, durability, and excellent shape‐memory performance, making them suitable for diverse structural and biomedical applications, such as adaptive medical devices, ergonomic shoe soles, and wearable biosensors. This novel material provides a versatile platform for high‐performance, 4D‐printed intelligent systems that address current challenges in polymer nanocomposites and advance engineering and biomedical innovations.