Multicomponent Modification of Polyethylene-Based Films for Enhanced Hydrophobicity and Balanced Gas Transport and...

Hydrophobic gas-permeable polyethylene films with balanced water vapor resistance and gas transport properties are desirable for membrane applications; however, achieving an effective balance between moisture barrier performance and gas permeability remains challenging. In this work, dense non-porous polyethylene-based composite films were fabricated through melt blending and film casting by incorporating fluorinated ethylene propylene copolymer (FEP), polyethylene wax (PE wax), and hydrophobic silica nanoparticles (SiO₂). The effects of multicomponent modification on surface properties, crystallization behavior, morphology, and transport performance were investigated. The optimized formulation, PEH-2, containing 3 wt% PE wax and 1 wt% hydrophobic SiO₂ based on the LLDPE/POE matrix, exhibited the most balanced transport performance. The synergistic regulation of surface energy, interfacial morphology, and diffusion pathways by FEP, PE wax, and SiO₂ enhanced hydrophobicity while maintaining CO₂ transport capability. The dense composite structure increased resistance to water vapor diffusion, whereas regulated molecular pathways facilitated CO₂ transport. PEH-2 exhibited a water contact angle of 110.75°, a CO₂ transmission rate of 6498 cm³·m^-2·day^-1 at 0.1 MPa, and a WVTR of 1.20 g·m^-2·day^-1. The CO₂ transmission rate/WVTR ratio (approximately 5.4 × 10³) was used to evaluate the balance between gas transport and moisture barrier performance. This study provides a scalable strategy for designing polyethylene-based composite membranes with balanced moisture resistance and gas transport properties.