Transparent Polyester Track-Etched/Aluminum Oxide Composite Membranes with Tunable Pore Size and Optical Transparency for Indoor Air Purification

The material candidates for optically transparent porous membranes with high removal efficiency for ultrafine dust are very limited. In this study, a composite polyester track-etched (PETE) membrane with a conformally passivated, ultrathin metal oxide layer is proposed as a transparent filter for air purification. The pore size of the resulting composite membrane was determined from the thickness of the alumina layer that was conformally deposited on the PETE membrane via atomic layer deposition. Maximum antireflection characteristics were achieved for alumina layer thickness of ~55 nm. The corresponding transmittance of the PETE/Al 2 O 3 composite membrane was ~81.3%. Compared with the pristine PETE membrane, the developed composite membrane showed improved filtration efficiency (~98.1% for PM1.0), possibly due to pore size reduction. The findings of this study demonstrate the potential use of the composite membrane as an aesthetic window filter to improve indoor air quality