Sustainable Nanocellulose-PEO Composites Reinforced with Functional Nanofillers in High-Performance Dielectric Nanocomposites for Green Flexible Electronics

The growing demand for sustainable materials in green flexible electronics calls for alternatives to petroleum-derived polymers, which are non-biodegradable, resource-intensive, and environmentally harmful. This study presents the fabrication of bio-composite films using water hyacinth derived cellulose nanofibrils (CNF), blended with polyethylene oxide (PEO) and reinforced by functional nanofillers such as barium titanate (BTO), silver nanowires (SNP), and carbon nanotubes (CNT). The nanocomposite films (NCF) were produced by solution casting and systematically characterized for morphological, dielectric, mechanical, thermal, and chemical properties. Scanning electron microscopy analysis revealed well-dispersed CNF (-30 nm diameter) uniformly embedded within a CNF/PEO matrix and nanofillers (0.5–2%). Dielectric testing showed that BTO significantly enhanced permittivity (>200), making it promising for capacitor and antenna applications, although dielectric loss increased at higher nanofiller loadings. SNP-reinforced NCF exhibited moderate permittivity (50–90) but higher dielectric loss (0.15–0.32), supporting multifunctional applications requiring both dielectric and conductivity. CNT reinforced with NCF provided a balanced performance, with stable permittivity, relative low dielectric loss (< 0.015) and superior mechanical flexibility. Mechanical testing confirmed that BTO increased stiffness and tensile strength (1.5–2%), SNP enhanced strength but reduced ductility up to 1.5%, and CNT offered reinforcement at 1.5% with preserved elongation (up to 6%). FTIR spectra indicated strong interfacial interactions between nanofillers and CNF-PEO matrix. Thermal analysis revealed that CNT disrupted the crystalline structure of the matrix, lowering melting and crystallization temperatures, whereas BTO and SNP had negligible thermal effects. This study demonstrates a sustainable pathway to valorize an invasive species into a biodegradable, high-performance NCF for sustainable electronics, signifying a pathway toward flexible antenna, sensors, and energy storage materials.