Enhancing the multifunctional properties of polycaprolactone/chitosan films with zirconium dioxide nanoparticles for biomedical and flexible optoelectronic applications

Abstract

This study addresses the growing need for sustainable and multifunctional materials by developing novel polycaprolactone (PCL)/chitosan (CS)/zirconium dioxide (ZrO₂) nanocomposite films. While PCL and CS offer biocompatibility and biodegradability, their combined use presents limitations for advanced applications requiring specific functional features. The incorporation of ZrO₂ nanoparticles aims to overcome these limitations and create materials with enhanced mechanical, electrical, optical, and antibacterial properties. The nanocomposites were synthesized via a simple casting method, and their properties were comprehensively characterized. Results show that the addition of ZrO₂ significantly improves the mechanical, electrical, optical, and antibacterial characteristics of the PCL-CS copolymer. Specifically, a 2 wt% ZrO₂ concentration yielded an optimal balance of mechanical strength, stiffness, ductility, and toughness, with a 63% increase in ultimate tensile strength and a 93% increase in toughness compared to neat PCL-CS. The electrical conductivity was significantly enhanced with increasing ZrO₂ content and temperature, and the dielectric properties were improved, positioning ZrO₂ as a mid-range dielectric filler. Optical analysis revealed that ZrO₂ content tunes the absorbance, energy gap, and refractive index, making these films suitable for optical applications. Furthermore, the nanocomposites exhibited remarkable antibacterial activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, with inhibition zones increasing with ZrO₂ concentration, demonstrating the synergistic effect between chitosan and ZrO₂. These findings highlight the potential of PCL-CS/ZrO₂ nanocomposite films as versatile and sustainable alternatives for a wide range of applications, including biomedical devices, flexible optoelectronics, and smart packaging.