Sustainable Energy Harvesting Using 3D Printed Self-Healing Cellulose-Derived Composites Reinforced with Yeast and Graphene

Abstract Development of sustainably processed ecofriendly composites is essential for advancing environmentally responsible 2D material-based flexible electronic platforms. Here, we present a PVA/CMC-YG layered composite, a lightweight and mechanically robust carboxymethyl cellulose-yeast-graphene (CMC-YG) material fabricated on a polyvinyl alcohol (PVA) substrate through the 3D printing process. Graphene was produced through a chemical-free passive exfoliation route using yeast, which naturally intercalates, attaches, and mechanically shears graphite during budding and reproduction. The resulting yeast-graphene (YG) dispersion, blended with carboxymethyl cellulose (CMC), produces a polymer composite ink with enhanced rheological properties. Compared to CMC, CMC-YG ink showed a 31% higher consistency index, and storage modulus (G′) in the linear viscoelastic region at 1% strain increased from 27.3 to 33.5 Pa, enhancing structural strength, retaining shape after printing, and reducing substrate penetration. The PVA/CMC-YG layered composite integrates clean, strongly bonded interfaces, efficient thermoregulation, and good mechanical performance, featuring minimal delamination and self-healing capability. The composite also delivers promising triboelectric outputs +40/-36.8 V and +6/-6.8 V in tapping and bending modes, respectively. Collectively, these properties establish the PVA/CMC-YG layered composite as a strong candidate for sustainable and self-powered, thermoregulating wearable sensors.