AVS 49th International Symposium
    Biomaterials Wednesday Sessions
       Session BI-WeP

Paper BI-WeP13
X-ray PhotoEmission Electron Microscopy of Polymeric Thin Films

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Biointerfaces and Surfaces II
Presenter: A.P. Hitchcock, McMaster University, Canada
Authors: A.P. Hitchcock, McMaster University, Canada
C. Morin, McMaster University, Canada
S.G. Urquhart, University of Saskatchewan, Canada
Correspondent: Click to Email
Patterned thin polymer films are of increasing importance in biomaterials, displays, electronic materials, etc. High spatial resolution, high chemical sensitivity analytical microscopy techniques are needed to optimize these systems. We are using X-ray Photoemission Electron Microscopy (X-PEEM) for chemical imaging of phase segregated polymer blends, patterned biomaterials for non-fouling and bio-passivatable applications, and interactions of test proteins with these surfaces. Optimization of X-PEEM has been optimized for insulating, radiation sensitive organic thin films. Polystyrene (PS) and poly(methyl methacrylate) (PMMA) are completely immiscible and thus PS/PMMA blends may be a suitable model for patterned biomaterial-protein interactions. Spun cast thin film blends of mono-disperse high (1 Mdalton) and low (100 Kdalton) PS and PMMA with bulk compositions from 66/33 w/w up to 10/90 w/w PS/PMMA have been studied by X-PEEM and atomic force microscopy (AFM).@footnote 1@ C 1s X-PEEM shows that there is significant enrichment of PS at the surface relative to the bulk and that the PMMA-rich domains contain PS. AFM shows the latter is a consequence of incomplete phase segregation, which results in a bimodal distribution of PS domain sizes, with the PS signal in PMMA domains arising from very small PS domains at the surface. This contribution will report on alternative techniques to prepare fully surface segregated PS-PMMA blends, and the outcome of protein attachment studies to these surfaces. X-ray microscopy carried out at the Advanced Light Source (supported by DoE under contract DE-AC03-76SF00098) and the Synchrotron Radiation Centre (supported by NSF under award DMR-0084402). Research supported financially by NSERC (Canada) and the Canada Research Chair Program. We thank the PEEM-2 staff (A. Scholl, A. Doran) for assistance in these studies. @FootnoteText@ @footnote 1@ C. Morin et al., J. Electron Spectroscopy 121 (2001) 203.