Fig. 4: STEM and elemental analysis of selected submicrometre particles.

The particle morphology revealed by STEM and elemental analysis of selected submicrometre particles excludes the possibility of the particles being N- or Si-containing additives. a,b, STEM images showing different morphologies of submicrometre particles released from Fleece samples during washing with nanopure water and centrifuged onto a TEM grid. c, The morphology of the particle highlighted in blue in b with a size of about 1,000 nm under higher magnification. d, HAADF image of the particle shown in c. e–g, Elemental distribution maps of carbon (e), oxygen (f) and silica (g) for the particle shown in c. Additional HAADF images and elemental distribution maps as well as the complete EDX spectrum are shown in Supplementary Figs. 4 and 5. The particles contain mainly hydrogen, carbon and oxygen, in accord with the molecular formula of PET.