Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Images of polytetrafluoroethylene (PTFE) surfaces obtained using atomic force microscopy (AFM). The PTFE surfaces have been treated with a radio frequency plasma torch for different exposure times as indicated in the figure: 0 min (original surface), 2 min, 26 min, and 50 min. The resulting root-mean-square roughnesses are 22 nm, 33 nm, 68 nm, and 150 nm, respectively (adapted from [135]).
