Hydrophobic PVDF-Based Electrospun Nanofibrous Membranes: Design Criteria Fabrication and Resistance to Long-Term Hydrodynamic Operation

Abstract

The mechanical integrity of electrospun nanofiber membranes (ENMs) under operational conditions may limit their application in membrane contactors. This study integrated the electrospinning (ESP) with heat treatments to enhance nanofiber integrity in polyvinylidene fluoride (PVDF) ENMs. The impact of ESP parameters on the properties of the resulting ENMs was explored, including polymer dope flow rate (1.0–1.2 mL h−1), tip-to-collector distance (TCD, 12–18 cm), and needle size (20–22 Ga), along with collector type (flat or rotary drum), needle motion (static or moving at 10 cm s−1), and collector rotation speed were assessed. Heat treatment was evaluated at 130°C–170°C for 1–15 h. The optimized ENM exhibited a 134° ± 5° water contact angle, 200 ± 50 μm thickness, and 3.10 ± 0.02 mg cm−2 surface density. It was fabricated using a 1.20 mL h−1 polymer dope flow rate, 12 cm TCD, and a static 20 Ga needle during an 8-h ESP session with a rotary collector, followed by treatment at 150°C under 70 Pa for 6 h. It endured over 800 h under high hydraulic stress (21 L h−1 water flow), outperforming a commercial PVDF membrane and highlighting its potential for long-term operation in gas–liquid membrane contactor applications.