title: Depth profiling of poly(L-lactic acid)/triblock copolymer blends with time-of-flight secondary ion mass spectrometry.
abstract: Time-of-flight secondary ion mass spectrometry employing an SF5+ polyatomic primary ion source was utilized to obtain a series of in-depth profiles from PLLA/Pluronic-P104 (poly(ethylene oxide-co-propylene oxide) triblock copolymer) blends in attempts to quantify the in-depth surface segregated Pluronic region. The resultant in-depth profiles were consistent with theoretical models describing the surface segregated region in polymeric blends and copolymer systems, with a surface enriched Pluronic-P104 region, followed by a P104 depletion layer, and finally a constant composition bulk region. These results were consistent over a range of concentrations (1-25%). The depth profiles obtained using cluster SIMS were compared to information obtained using X-ray photoelectron spectroscopy. The results demonstrate that, with cluster primary ion bombardment, we are for the first time able to quantify the polymeric composition as a function of depth within certain multicomponent polymer blends. This success can be attributed to the sputter characteristics of polyatomic primary ion bombardment (SF5+) as compared to monatomic primary ion beams.
authors.affiliation: Chemical Science and Technology Laboratory, Surface and Microanalysis Science Division, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, Maryland 20899, USA. christine.mahoney@nist.gov
authors.forename: Christine M
authors.initials: CM
authors.lastname: Mahoney
authors.forename: Jinxiang
authors.initials: J
authors.lastname: Yu
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Gardella
mesh_terms: D008567:Membranes, Artificial; D011092:Polyethylene Glycols / Q000032:analysis*; D011108:Polymers / Q000032:analysis; D011409:Propylene Glycols / Q000032:analysis*; D012680:Sensitivity and Specificity; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D013053:Spectrophotometry / Q000379:methods; D013499:Surface Properties; D014965:X-Rays
chemical_list: D008567:Membranes, Artificial; C116176:PEO-PPO-PEO; D011108:Polymers; D011409:Propylene Glycols; C012504:polypropylene glycol; D011092:Polyethylene Glycols