Work

Hierarchically structured silica-reinforced PLA nanofibrous membranes with enhanced anti-wetting and mechanical stability for air-gap membrane distillation

Year: 2026

Type: article

Abstract: This study presents a hierarchically structured biodegradable superhydrophobic polylactic acid (PLA)/fumed silica (FS) nanofibrous membrane for anti-wetting air-gap membrane distillation (AGMD). Unlike biodegradable membrane studies that primarily rely on post-fabrication surface modification, hydrophobic FS nanoparticles were directly incorporated into the PLA spinning solution through a one-step electrospinning process, enabling intrinsic control of fiber morphology, pore structure, surface roughness, and wettability throughout the membrane matrix. Subsequent post-heat treatment reinforced inter-fiber bonding while preserving the porous architecture for vapor transport. FS incorporation reduced fiber diameter from 810 to 627 nm and pore size from 1.37 to 0.70 µm, promoting a rough surface favoring the Cassie–Baxter wetting state. The optimized membrane (S4, 7 wt% FS) exhibited a water contact angle of 154°, liquid entry pressure of 38 kPa, elastic modulus of 166 MPa, and enhanced thermal stability with an onset degradation temperature of 330 °C. Through comprehensive characterization techniques such as FE-SEM, AFM, gloss analysis, air permeability, nanoindentation, and mechanical testing, significant enhancements in membrane integrity and anti-wetting properties were observed. Nanoindentation results indicated improvements in both hardness and modulus compared to the original PLA membranes. During AGMD desalination, the optimized membrane consistently achieved a permeate flux of 3.1 kg/m 2 h, with salt rejection rates surpassing 99 % for a 3.5 wt% NaCl feed solution. The enhanced performance was attributed to synergistic effects of hierarchical roughness, pore regulation, mechanical reinforcement, and improved wetting resistance. These findings demonstrate a sustainable strategy for developing high-performance biodegradable membranes as alternatives to petroleum-derived MD materials.

Source: Nanotechnology Reviews

DOI: 10.1515/ntrev-2025-0390