Thermodynamically controlled surface segregation of perfluoroalkyl-end-capped PMMA as investigated by low energy ion scattering (LEIS)

Low MW PMMA prepd. by atom transfer radical polymn. (ATRP) was blended with a perfluoroalkyl-end-capped PMMA (Rf-PMMA) synthesized also by ATRP. Thin films were prepd. by spin casting the polymer blend solns. in toluene. Fluorinated species became enriched at the film surface, evidenced by increased contact angles for both water and hexadecane. The temp.-dependent fluorine concn. in the outermost one layer was quant. detd. by low energy ion scattering (LEIS). The fluorine concn. decreased significantly upon the increase of the temp. when the temp. was above the glass transition temp. of polymers. The surface segregation of fluorinated species at temps. above the Tg of polymers appears to be thermodynamically controlled. [on SciFinder (R)]