Free-Standing Polyurethane Nanofiber/Nets Air Filters for Effective PM Capture

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Engineering

Background:

• Nanofiber air filters face limitations in filtration performance and light transmittance due to thick fibers and large pores.
• Developing substrate-free nanofiber membranes with nanoscale diameters and ultrathin structures is challenging.

Purpose of the Study:

• To create robust, substrate-free polyurethane (PU) nanofiber/nets air filters for efficient particulate matter (PM) capture.
• To achieve high filtration efficiency, light transmittance, and mechanical strength in the developed filters.

Main Methods:

• Utilized a combination of electrospinning/netting and a facile peel-off process from designed substrates.
• Incorporated ionic liquid inspiration and optimized surface structures of receiver substrates.
• Constructed free-standing membranes from bonded nanofibers and 2D nanonets with nanoscale diameters (≈20 nm).

Main Results:

• Achieved high PM_1-0.5 removal efficiency (>99.00%) and PM_2.5-1 removal efficiency (>99.73%).
• Maintained high light transmittance (≈70%) and low pressure drop (28 Pa).
• Demonstrated >99.97% removal efficiency for PM_0.3 with ≈40% transmittance and robust purification of real smoke PM_2.5.

Conclusions:

• The developed free-standing PU nanofiber/nets filters are promising for high-efficiency and transparent air filtration.
• The strategy overcomes challenges in creating ultrathin, substrate-free nanofiber membranes for particulate matter capture.
• These filters show potential for diverse filtration and separation applications requiring high performance and transparency.