Optical transparency and moisture permeability governed by thermally induced Interfiber bonding in hierarchical...

Conventional nanofiber membrane materials exhibit opacity owing to substantial light loss inherent to their structural characteristics, resulting in the invisibility of the face in their product applications, such as masks. In addition, the absence of moisture transfer channels promotes moisture accumulation. To address these limitations, electrospinning technology combined with selective interfiber thermal melting for pore formation has the potential to effectively improve transparency and construct effective mass transfer channels, thereby mitigating structural defects and potentially addressing these performance issues.

Electrospun nanofiber membranes consisting of ethylene vinyl acetate (EVA) and polyacrylonitrile (PAN) nanofibers with physically interlocking structures were fabricated. The selective melting of the EVA nanofiber at 80 °C formed mass transfer channels. Additionally, the composite performance of three-dimensional mass transfer channels with transparency, filtration, and moisture permeability properties was analyzed by validating the structural characterization and mass transfer mechanism studies.

The selective fusion of EVA nanofibers formed an optimized light path and achieved the transparency of the nanofiber membranes. Concurrently, EVA and PAN nanofibers established a layered coarse-fine gradient filtration system and moisture-transfer channels. This effectively resolves the traditional performance trade-offs among transparency, protection, and moisture management in nanofiber membranes. The prepared nanofiber materials exhibited a light transmittance of 84.14 % at 550 nm, filtration efficiency of 94.18 % (85 L/min) for PM_0.3 particles, moisture permeability of 5.52 g m^-2 h^-1, and air permeability of 119.59 mm s^-1.