Just got that article recommended to me in chrome and came here to check if anyone commented.
I would think this was well known much earlier but looking at this and their previous paper it's actually quite interesting.<p>BTW title is slightly misleading, this is about triboelectricity<p><a href="https://pubs.acs.org/doi/10.1021/acs.nanolett.4c03656#" rel="nofollow">https://pubs.acs.org/doi/10.1021/acs.nanolett.4c03656#</a>