Tuneable Graphite-to-Graphene Transformation via Microwave-Assisted Time Dependent Treatment Using Natural Gum Arabic: A Green Route to Graphene Inks for Flexible Electronics

This work presents a microwave-assisted, physiochemically driven exfoliation approach for the rapid synthesis of graphene from graphite using an aqueous gum Arabic medium. Under microwave irradiation, gum Arabic undergoes acidic transformation, generating reactive carboxyl and hydroxyl groups that intercalate into graphite galleries, weaken π–π stacking, and induce layer separation due to microwave-induced thermal shock and dielectric heating. By controlling microwave-irradiation time, the process selectively yields exfoliated graphite, reduced graphene oxide, or few-layer graphene, establishing a user-controlled, green, and scalable synthesis pathway. Comprehensive structural and morphological analyses (XRD, Raman, HRSEM, HRTEM) confirm the formation of few-layered, high-crystallinity graphene with sheet-like morphology. The resulting graphene was formulated into a green conductive ink using cellulose acetate butyrate (CAB) as a binder, exhibiting pseudoplastic rheology, low sheet resistance, and remarkable flexibility. Screen-printed devices fabricated with this ink demonstrated efficient thermoelectric, humidity, temperature, and real-time strain sensing, confirming its multifunctional applicability. This study highlights the synergistic effect of microwave-induced physiochemistry and bio-acidic exfoliation, offering a low-cost, sustainable, and application-ready graphene platform for next-generation flexible and printed electronic systems.