Enhanced Triboelectric Charge Stability by Air-Stable Radicals

This paper demonstrates that air-stable radicals enhance the stability of triboelectric charge on surfaces. While charge on surfaces is often undesirable (e.g., static discharge), improved charge retention can benefit specific applications such as air filtration. Here, it is shown that self-assembled monolayers (SAMs) containing air-stable radicals, 2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO), hold the charge longer than those without TEMPO. Charging and retention are monitored by Kelvin Probe Force Microscopy (KPFM) as a function of time. Without the radicals on the surface, charge retention increases with the water contact angle (hydrophobicity), consistent with the understanding that surface water molecules can accelerate charge dissipation. Yet, the most prolonged charge retention is observed in surfaces treated with TEMPO, which are more hydrophilic than untreated control surfaces. The charge retention decreases with reducing radical density by etching the TEMPO-silane with tetrabutylammonium fluoride (TBAF) or scavenging the radicals with ascorbic acid. These results suggest a pathway toward increasing the lifetime of triboelectric charges, which may enhance air filtration, improve tribocharging for patterning charges on surfaces, or boost triboelectric energy harvesting. This paper reports a strategy for enhancing triboelectric charge stability by depositing air-stable radicals on a surface. By utilizing AFM probes to precisely induce triboelectric charge on self-assembled monolayers, it is demonstrated that air-stable radicals help triboelectric charge sustain & AP;3x longer than without the radicals. This concept opens up the possibility to extend the lifetime of air filtration systems, including masks.image

Automated summary

This paper demonstrates that air-stable radicals enhance the stability of triboelectric charge on surfaces. The charge retention is shown to increase with hydrophobicity, but the most prolonged charge retention is observed in surfaces treated with TEMPO, which are more hydrophilic. The charge retention decreases with reducing radical density by etching the TEMPO-silane or scavenging the radicals.