title: Surface characterization by XPS, contact angle measurements and ToF-SIMS of cellulose fibers partially esterified with fatty acids.
abstract: The topochemistry of the controlled heterogeneous esterification of cellulose fibers with fatty acid chlorides of different chain length, both in swelling and non-swelling media, was assessed by X-ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and contact angle measurements. On the one hand, the results provided by the combined use of these three powerful techniques showed unambiguously the occurrence of the reaction at the fibers' surface and, on the other hand, the XPS results showed that the surface coverage with the fatty acid moieties increased with their chain length, but was only modestly affected by the degree of substitution (DS), suggesting that when the esterification yield was increased (higher DS values), an in-depth reaction also occurred, particularly when DMF was used as a cellulose swelling medium, involving the OH groups buried below the fibers' surface.
authors.affiliation: CICECO and Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal. cfreire@dq.ua.pt
authors.forename: Carmen S R
authors.initials: CS
authors.lastname: Freire
authors.forename: Armando J D
authors.initials: AJ
authors.lastname: Silvestre
authors.forename: Carlos
authors.initials: C
authors.lastname: Pascoal Neto
authors.forename: Alessandro
authors.initials: A
authors.lastname: Gandini
authors.forename: Pedro
authors.initials: P
authors.lastname: Fardim
authors.forename: Bjarne
authors.initials: B
authors.lastname: Holmbom
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D004126:Dimethylformamide; D004951:Esterification; D005227:Fatty Acids / Q000737:chemistry*; D005559:Formamides / Q000737:chemistry; D008422:Materials Testing / Q000379:methods*; D018629:Spectrometry, Mass, Secondary Ion; D013057:Spectrum Analysis; D013499:Surface Properties; D014965:X-Rays
chemical_list: D001672:Biocompatible Materials; D005227:Fatty Acids; D005559:Formamides; D004126:Dimethylformamide; D002482:Cellulose