In the version of this Article originally published, in the first paragraph of the Methods, HFE was incorrectly given as 2,2,2-Trifluoroethyl-3',3',3',2',2'-pentafluoropropyl ether; it should have been 1,1,2,2-tetrafluoroethyl-2',2',2'-trifluoroethyl ether. This has now been corrected in the online versions of the Article.