Electrospun Polyacrylonitrile/Polycaprolactone Janus Nanofibers With Partial Degradation for Retaining a High Air Filtration Performance

ABSTRACT This study presents the innovative fabrication of Janus polyacrylonitrile/polycaprolactone (PAN/PCL) nanofibrous membranes using a customized side‐by‐side electrospinning technique for sustainable high‐performance air filtration. The designed eccentric spinneret enables the continuous production of biphasic nanofibers, combining PAN's mechanical robustness (tensile strength: 1.45 ± 0.03 MPa) with PCL's controlled degradability. The resulting membranes exhibit exceptional filtration efficiency (98.4% for 0.3 μm particles) at a low pressure drop (152 Pa). Selective degradation of the PCL phase regenerates membrane porosity while preserving the PAN matrix, as confirmed by TEM, which reveals distinct PCL and PAN domains. The membranes maintain stable hydrophobicity and tunable light transmittance, making them suitable for applications in reusable personal protective equipment and transparent ventilation systems. This work establishes a sustainable filtration platform where controlled partial degradation extends service life without compromising performance, addressing the critical challenge of prolonged filtration efficiency in electrospun nanofiber filters.