We use the perfl uorocarbon-functionalized polymer, poly(4-((1H ,1H ,2H ,2H -perfl uorodecyl)-oxycarbonyl)styrene) [PPFOCS], as a model system with both surface molecular segregation and molecular orientation to test the capabilities of a near-edge X-ray absorption fi ne structure (NEXAFS) spectroscopy analysis scheme for polymer surfaces. Both NEXAFS spectroscopy and angleresolved X-ray photoelectron spectroscopy (XPS) show segregation of the − (CF2 )7 CF3 chain to the air/polymer interface with the styrenic portion underneath. Postedge analysis of the NEXAFS spectra indicates a low carbon atom density surface layer, of thickness 1.0− 1.4 nm, due to the overlayer of perfl uorocarbon chains. An analysis of the NEXAFS C 1s→ π*CC and C 1s → σ*C−F transitions accounting for the diff erent depth distributions of the phenyl rings and fl uorocarbon helices reveals strong orientational ordering with the orientational order parameter SCC for the phenyl ring equal to − 0.27 and for the C− F bonds in the fl uorocarbon helix SC−F equal to − 0.13. The SCC and SC−F determined for the polymer with the esterlinked side chain are considerably higher than those reported previously (− 0.039 and 0, respectively) for a polymer [poly(4- (1H ,1H ,2H ,2H -perfl uorodecyl)oxymethylstyrene)] with an identical side chain that was ether linked to the styrene phenyl ring. We tentatively attribute the high orientation in the PPFOCS to the partial conjugation between the ester group and the phenyl ring providing a relatively stiff linkage between the perfl uorocarbon helix and the phenyl ring.
Surface organization of a perfluorocarbon-functionalized polystyrene homopolymer
GALLI, GIANCARLO;
2012-01-01
Abstract
We use the perfl uorocarbon-functionalized polymer, poly(4-((1H ,1H ,2H ,2H -perfl uorodecyl)-oxycarbonyl)styrene) [PPFOCS], as a model system with both surface molecular segregation and molecular orientation to test the capabilities of a near-edge X-ray absorption fi ne structure (NEXAFS) spectroscopy analysis scheme for polymer surfaces. Both NEXAFS spectroscopy and angleresolved X-ray photoelectron spectroscopy (XPS) show segregation of the − (CF2 )7 CF3 chain to the air/polymer interface with the styrenic portion underneath. Postedge analysis of the NEXAFS spectra indicates a low carbon atom density surface layer, of thickness 1.0− 1.4 nm, due to the overlayer of perfl uorocarbon chains. An analysis of the NEXAFS C 1s→ π*CC and C 1s → σ*C−F transitions accounting for the diff erent depth distributions of the phenyl rings and fl uorocarbon helices reveals strong orientational ordering with the orientational order parameter SCC for the phenyl ring equal to − 0.27 and for the C− F bonds in the fl uorocarbon helix SC−F equal to − 0.13. The SCC and SC−F determined for the polymer with the esterlinked side chain are considerably higher than those reported previously (− 0.039 and 0, respectively) for a polymer [poly(4- (1H ,1H ,2H ,2H -perfl uorodecyl)oxymethylstyrene)] with an identical side chain that was ether linked to the styrene phenyl ring. We tentatively attribute the high orientation in the PPFOCS to the partial conjugation between the ester group and the phenyl ring providing a relatively stiff linkage between the perfl uorocarbon helix and the phenyl ring.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
