Polyaniline–Ionic Liquid Hybrid Coatings for Conductive Polyester Air Filters With Enhanced <scp>PM</scp> _0.3 Capture and Energy Efficiency

ABSTRACT Electrostatic filters suffer from charge decay and the inherent trade‐off between filtration efficiency and pressure drop. To enhance electrostatic functionality, we engineered polyester (PET) filter media coated with a conductive polyaniline–ionic liquid hybrid (PDA@PANI@IL) and directly compared their performance with PANI–MIL‐101(Cr) counterparts and bare PET. Under optimized conditions (48 m/min face velocity, 10 kV electrostatic charging), the PDA@PANI@IL medium achieved a PM 0.3 capture efficiency of 94%, significantly outperforming both the PANI–MOF variant (79.98%) and bare PET (53.69%). This represents a 76% relative improvement over bare PET and a 17.5% gain over the MOF‐based medium. The enhanced efficiency was accompanied by an increase in pressure drop from 59 Pa to 95 Pa—a 61% rise. The quality factor reached 0.029 Pa −1 at 48 m/min and up to 0.325 Pa −1 at lower velocity (6 m/min), both exceeding that of bare PET ( p &lt; 0.01, n = 3). XRD and FESEM analyses confirmed enhanced PANI crystallinity and a uniform, non‐pore‐blocking coating morphology. The superior performance is attributed to the PANI–IL hybrid's ability to stabilize surface charge and promote efficient electrostatic particle capture, even at high airflow rates. This work demonstrates that ionic liquid–assisted conductive polymer coatings offer a more effective and economically viable strategy than MOF‐based modifications for next‐generation electrostatic air filters, leveraging low‐cost, industrially scalable materials—polyaniline and ionic liquids—instead of expensive metal–organic frameworks.