Microwave‐Enabled Immobilization of Cu ₂ O on Cellulosic Paper for Antimicrobial Performance Against Gram‐Positive and Gram‐Negative Bacteria

Immobilization of Cu ₂ O on cellulose fibers has been successfully conducted by a microwave‐assisted synthesis approach at 60°C and 300 W power within 7 min. A Cu ₂ O loading of 15.3 wt% was achieved in this short experimental time without employing any linker, binder, or retention aid. The particle size of Cu ₂ O was estimated to be in the range from 260 nm to 1.3 µm. Paper sheets have been fabricated without (blank paper designated as BP) and with Cu ₂ O‐immobilized cellulosic fibers using a TAPPI (Technical Association of the Pulp and Paper Industry) Handsheet former, according to TAPPI test method 205 sp‐02. The immobilization of Cu ₂ O on paper matrices altered the surface hydrophilicity, resulting in a substantial increase in the contact angle, reaching up to 83°. The tensile strength was increased from 595 N/m in BP to 1303 N/m for Cu ₂ O‐immobilized matrices. The antimicrobial activity has been substantially improved in Cu ₂ O‐immobilized paper matrices against both Gram‐positive ( S. aureus ) and Gram‐negative ( E. coli ) bacterial species. A prominent inhibition zone of 6–18 mm against S. aureus and 6–16 mm against E. coli was observed within a 12‐h incubation period, accompanied by maximum % reduction in bacterial count of 98% and 95%, respectively, within 2 h of visible light exposure.