Fabrication of Polyethylene Fibrous Membranes via Supercritical CO 2 ‐Assisted Gel Preparation and Melt Differential Electrospinning

Melt electrospinning is considered a promising and scalable route for manufacturing polyethylene (PE) fibrous membranes. However, the high viscosity of polyethylene melts during melt electrospinning often leads to unstable jet deformation and poor membrane uniformity. In this work, an integrated processing strategy combining supercritical carbon dioxide (SC‐CO 2 )‐assisted gel preparation, melt differential electrospinning, low‐temperature pre‐hot‐pressing, and hot stretching was developed to fabricate high density polyethylene/ultra‐high molecular weight polyethylene (HDPE/UHMWPE) fibrous membranes. The SC‐CO 2 ‐assisted precursor gel exhibited lower complex viscosity and storage modulus, while Raman mapping of the resulting membrane revealed reduced spatial variation of the Raman spectral response. Pre‐hot‐pressing consolidated the fibrous network and helped maintain the structural integrity of the membrane during subsequent stretching. Hot stretching markedly enhanced the structural orientation and tensile strength of the fibrous membrane, with the machine‐direction (MD) tensile strength increasing from ca. 27.20 MPa to 72.65 MPa. Meanwhile, the intrinsic hydrophobicity of the polyethylene membrane was maintained. SC‐CO 2 was employed as a plasticizing medium to improve the uniformity of the gel precursor, thereby promoting the formation of a more uniform fibrous membrane and providing a practical strategy for preparing mechanically reinforced HDPE/UHMWPE fibrous membranes from highly entangled polyethylene systems.