title: Unique Combination of Surface Energy and Lewis Acid-Base Characteristics of Superhydrophobic Cellulose Fibers.
abstract: Cellulose fibers were first functionalized on their surface by silanization with trichloromethylsilane in an optimized gas-solid reaction, and the occurrence of the reaction was assessed using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Then, the changes in the physicochemical surface properties of the material were thoroughly assessed using inverse gas chromatography (IGC) and X-ray photoelectron spectroscopy as surface specific tools. A very surprising combination of results was obtained: (i) the dispersive component of the surface energy was found to decrease from 42 to 14 mJ m-2(at 40 °C), the latter figure representing one of the lowest values ever reported (by IGC) for cellulose-based materials, and (ii) both Lewis acidic and Lewis basic characters of the fiber surface, as measured by the injection into the IGC columns of 15 different vapor probes, significantly increased with silanization. Moreover, those remarkable changes in the surface properties of the material were obtained at a low degree of silanization (as shown by ATR-FTIR). The present results may have a great impact in what concerns the application of the described type of superhydrophobic cellulose fibers for the production of new biocomposites: an unusual enhanced compatibility both with low-surface energy polymeric matrices, such as polyolefins, as well as with other types of matrices through Lewis acid-base interactions, can be predicted.
authors.affiliation: Department of Chemical Engineering, CIEPQPF, University of Coimbra , Pólo II. R. Sílvio Lima, PT-3030-790 Coimbra, Portugal.
authors.forename: J A F
authors.initials: JA
authors.lastname: Gamelas
authors.affiliation: Sustainable Construction Division, TECNALIA , Área Anardi 5, 20730 Azpeitia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Salvador
authors.affiliation: Sustainable Construction Division, TECNALIA , Área Anardi 5, 20730 Azpeitia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Hidalgo
authors.affiliation: Department of Chemical Engineering, CIEPQPF, University of Coimbra , Pólo II. R. Sílvio Lima, PT-3030-790 Coimbra, Portugal.
authors.forename: P J
authors.initials: PJ
authors.lastname: Ferreira
authors.affiliation: Sustainable Construction Division, TECNALIA , Área Anardi 5, 20730 Azpeitia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Tejado
mesh_terms: D000327:Adsorption; D002482:Cellulose / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D058116:Lewis Acids / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D058116:Lewis Acids; D012821:Silanes; D002482:Cellulose