Urchin-like WO[sub.3] Particles Form Honeycomb-like Structured PLA/WO[sub.3] Nanocomposites with Enhanced Crystallinity, Thermal Stability, Rheological, and UV-Blocking and Antifungal Activity

The development of poly(lactic acid) (PLA) nanocomposites incorporating urchin-like WO[sub.3] particles through a cost-effective solution-casting method has led to significant enhancements in structural, thermal, optical, and rheological properties. The incorporation of these WO[sub.3] particles up to 7 wt% resulted in the formation of an irregular honeycomb-like morphology with broad pore sizes ranging from 14.1 to 24.7 µm, as confirmed by SEM and EDX analysis. The urchin-like WO[sub.3] particles acted as effective nucleating agents, increasing the crystallinity of PLA from 40% to 50% and achieving an impressive overall crystallinity rate of 97%. Differential scanning calorimetry (DSC) revealed an 11 K reduction in the crystalline phase transition temperature while maintaining stable melting (Tm) and glass transition (Tg) temperatures. Thermal analysis indicated a significant decrease in the onset of degradation and maximum thermal stability (T[sub.max] ), with a reduction of 21 K due to the incorporation of the WO[sub.3] particles. Optical measurements showed enhancement of UV-blocking properties from 9% to 55% with the WO[sub.3] particle loading. Rheological tests demonstrated substantial improvements in viscoelastic properties, including a remarkable 30-fold increase in storage modulus, suggesting enhanced gel formation. Although the nanocomposites showed minimal antibacterial activity against Escherichia coli and Staphylococcus aureus , they exhibited significant antifungal activity against Candida albicans . These results underscore the potential of the PLA/WO[sub.3] nanocomposites for advanced material applications, particularly where enhanced mechanical, thermal, optical, and antifungal performance is required.