rGO and rGO/Fullerene Coatings on Blended Textile Fabrics: Characterization of Doctor Blade and Dip Coating Methods

Coating method significantly influences how graphene derivatives perform on textile fibers, especially blended substrates where fiber chemistry varies. Graphene oxide (GO) and GO/fullerene composites were deposited on a blended fabric (45% PET, 25% viscose, 8% elastane, 22% recycled PET) using doctor blade and dip coating, followed by chemical reduction to rGO. Three thickness levels were applied for each method: blade gap settings of 50, 100, and 150 µm for doctor blade coating, and immersion times of 30 s, 2 min, and 5 min for dip coating. A more concentrated, higher-viscosity GO dispersion was prepared for doctor blade coating. FTIR spectra showed spectral changes consistent with chemical reduction in GO, including attenuation of hydroxyl-related absorption bands. Electrical resistivity and mechanical properties were determined via conductivity measurements and tensile testing. Doctor blade coatings achieved 0.81 kΩ/sq for rGO/fullerene at the highest thickness, 27 to 70 times lower than dip-coated samples (22.1-56.9 kΩ/sq), depending on coating material and level. The difference reflects uniform blade deposition on hydrophobic polyester fibers, whereas immersion leads to uneven particle distribution. Fullerene addition reduced sheet resistance by approximately fivefold. Mechanical testing showed that coating did not degrade fabric integrity; elongation values remained above 70% across all samples, with most exceeding 80%. These results suggest that, under the present processing conditions, the lower sheet resistance was mainly related to the more continuous coating morphology obtained by doctor blade coating.