[kmlx]

gore-tex already solved this.

[ianburrell]

Gore-tex is the same as other breathable water-resistant fabrics. They uses DWR, a form of PTFE, but sounds like switching to something better.

The difference with original 3-layer Gore-Tex is that membrane is protected so lasts longer.

[wiml]

With PTFE. I'm not sure what the vague term "forever chemical" covers but PTFE is a perfluorinated alkane and is pretty "forever"ish.

[_yb2s]

Gore-tex only works if also coupled with PFAS DWR coatings on the outside. Otherwise the “pores” are clogged with a sheet of water, and cannot breathe.