A team of researchers from Chung-Ang University and Pusan National University, both in the Republic of Korea, has developed a regenerative coating that enhances air filters' ability to capture and trap airborne particles.

This addresses a challenge for many commercial air filters, which allow for some captured particles to detach from the filter and re-enter the air, thanks to weak adhesive forces. Such designs threaten to reduce air filtration efficiency and shorten air filter lifespan.

Source: Professor Sanghyuk Wooh, Chung-Ang University, Republic of Korea and Professor Chae Bin Kim, Pusan National University, Republic of Korea

As such, the team developed a self-renewing adhesive coating — called dynamic imine bond adhesive (DIBA) — that repeatedly exposes fresh sticky surfaces by moving captured particles deeper into the adhesive.

In the lab, the team spray-coated a thin DIBA layer onto commercially available air filter media and then assessed its chemical, mechanical and adhesive properties via rheology, Fourier-transform infrared spectroscopy, atomic force microscopy and microscopy. The team then assessed the material’s filtration efficiency, pressure drop, particle resuspension, high-speed airflow performance and long-term durability.

The DIBA coating improved particle retention by forming self-renewing, capillary-driven adhesive bridges around captured particles, increasing adhesion by roughly 70-fold. During trials, it boosted filtration efficiency by 10% to 30% without increasing pressure drop, improved performance from minimum efficiency reporting value (MERV) 6 to MERV 11 and nearly doubled filter lifespan by delaying clogging.

The team suggests that the technology promises to improve filtration systems that require both high particle capture efficiency and long service life, including HVAC systems, home air purifiers, industrial dust collectors, cleanrooms, automotive cabin filters and personal protective equipment.

An article detailing the coating, “A Super-Adhesive Air Filter With Capillarity-Mediated Spontaneous Particle Absorption via Dynamic Bond Exchange,” appears in the journal Advanced Materials.