AVS 45th International Symposium
    Biomaterial Interfaces Group Monday Sessions
       Session BI-MoP

Paper BI-MoP1
Molecular Structure of Protein-Resistant Plasma-Deposited Oligoglyme, Dioxane, and Crown Ether Films

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Biomaterial Interfaces Poster Session
Presenter: E.E. Johnston, University of Washington
Authors: E.E. Johnston, University of Washington
B.D. Ratner, University of Washington
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Poly(ethylene oxide)-like (PEO-like) films are of interest as biomaterials for their ability to resist protein adsorption and cellular attachment.@footnote 1,2@ Here we compare the chemistry and molecular structure of PEO-like films that were plasma deposited from linear and cyclic ether rich precursors. The plasma precursors consist of a series of four linear oligo ethylene glycol dimethyl ethers (oligoglymes) (CH@sub 3@-O-(CH@sub 2@CH@sub 2@O)@sub n@-CH@sub 3@, n = 1-4) and a corresponding series of cyclic oligomers -(CH@sub 2@CH@sub 2@O)@sub m@-: dioxane, (m=2); 12-crown-4 ether, (m=4); and 15-crown-5 ether (m=5). Analysis by x-ray photoelectron spectroscopy (XPS), and time of flight SIMS (TOF-SIMS) will be reported. The view emerging from the analysis is that oligoglyme plasma deposited films consist of a carpet of randomly branched, methyl-terminated chains of -(CH@sub 2@CH@sub 2@O)- repeat units. The films are generally free of hydroxyl groups and hydrocarbonaceous domains. Films from larger molecular weight precursors contain longer fragments of intact monomer suggesting that the films are more loosely crosslinked. Proposed models of the oligoglyme PDF surface structure can account for many aspects of the high mass TOF-SIMS spectra. Interpretation of the crown ether PDF spectra was more difficult than that of the oligoglyme films. On the basis of the (45/43+45) positive ion ratio analysis and adventitious binding of sodium and potassium cations it is concluded that the outermost surface of crown ether films consist predominantly of intact cyclic fragments. TOF-SIMS analysis of dioxane films suggests the presence of hydroxyl groups pendant to an unsaturated hydrocarbonaceous matrix and the presence of ether-carbon bearing precursor fragments. @FootnoteText@ @footnote 1@ L@aa o@pez, G. P.; Ratner, B. D.; Tidwell, C. D.; Haycox, C. L.; Rapoza, R. J.; Horbett, T. A. J. Biomed. Mater. Res. 1991, 26, 415-436. @footnote 2@ Johnston, E. E., PhD dissertation, University of Washington, 1997.