Electrospinning of cellulose acetate membranes: optimization of properties for fuel cell applications

Abstract

Electrospinning of cellulose acetate membranes for low‑temperature fuel cells was investigated. Solutions containing 1, 3, 5, 7, 10 and 12 wt % polymer were prepared in acetone–dimethylformamide mixtures of 6:4 and 4:6 and homogenised by centrifugation. Rotational rheometry revealed a linear shear‑stress–rate relation; for the 5 % solution at 6:4, raising the feed rate from 0.3 to 1.0 mL h⁻¹ increased shear stress from 52.5 to 106.1 kPa. Dynamic viscosity rose from 9.6 to 13.8 Pa s when polymer content increased from 14 to 15 %. Electrospinning at 30 kV and a 100 mm gap produced fibres evaluated by optical and scanning electron microscopy. A 6 % solution yielded mean diameters of 0.61–0.79 µm; increasing concentration to 8 % narrowed the distribution, whereas 12 % produced greater heterogeneity owing to higher viscosity. The asymmetry coefficient was lowest for 6–8 % polymer at a 6:4 solvent ratio. Reducing the feed rate to 0.3 mL h⁻¹ decreased fibre diameter, while 1.0 mL h⁻¹ caused thickening. The optimal window comprises 6–8 % cellulose acetate, solvent ratio 6:4 and feed rate 0.3–0.7 mL h⁻¹. Membranes produced under these conditions exhibit uniform morphology and are suitable for incorporation into membrane–electrode assemblies. The study demonstrates precise structural control through tuning of rheological and electrohydrodynamic parameters, providing a basis for industrial scale‑up and further optimisation of fuel‑cell energy efficiency. Environmental impact is minimised through solvent reuse and low processing temperatures.