Mechanical and transport properties of fibrous amorphous silica meshes and membranes fabricated from compressed electrospun precursor fibers

Abstract

Highly porous, 0.1–1.5 mm thick fibrous amorphous silica (FAS) meshes with 500 ± 200 nm fiber diameters were prepared from the precursor fibers made by a high-yield free-surface alternating field electrospinning (AFES) process. A combination of mild thermal and pressure treatment of the fibrous precursor material before the calcination step was used to tailor the mechanical and transport properties of the resulting FAS structures. Compression of the as-spun material determined the resulting porosity, effective fiber diameter, and microarchitecture of the FAS structures when calcined between 600 and 1000 °C. Flexible FAS meshes and membranes revealed the tensile strength and modulus up to 1.4 MPa and 580 MPa, respectively, and Darcy'S permeability coefficient in a range of 1.2 × 10−12–1.6 × 10−11 m2. Taking into consideration the compression-dependent effective fiber diameter, the permeability of compressed FAS membranes fitted the models developed for two-dimensional fibrous layer architectures with partial fiber alignment within the stacked layers.