Designing Nanotextured Vanadium Oxide-Based Macroscopic Fibers: Application as Alcoholic Sensors Ce ´line M. Leroy, ² Marie-France Achard, ² Odile Babot, ‡ Nathalie Steunou, § Pascal Masse ´, ² Jacques Livage, § Laurent Binet, § Nicolas Brun, ² and Re ´nal Backov* ,² Centre de Recherche Paul Pascal, UPR 8641-CNRS, 115 AVenue Albert Schweitzer, 33600 Pessac, France, Institut des Sciences Mole ´ culaires (ISM), UMR-5082 CNRS, UniVersite ´ Bordeaux-I, 351 cours de la libe ´ ration, 33045 Talence Cedex, France, and Laboratoire de Chimie de la Matie ´ re Condense ´ e, UMR-7574 CNRS, 4 Place Jussieu, UniVersite ´ Pierre et Marie Curie, France ReceiVed May 3, 2007 Composite vanadium oxide/PVA/latex macroscopic fibers have been generated by using an extrusion process. Specifically, inorganic vanadium oxide fibers enable the detection of 0.1 ppm of ethanol within 3-5 s at 42 °C, which is certainly one of the highest sensitivities to date concerning alcohol sensors. More importantly, by varying the starting latex inclusion contents, the shear rates applied during the extrusion process, and the final appliance of a thermal treatment, we were able to segregate each parameter involved within the mechanical and sensing properties associated with these as-synthesized fibers, i.e., the amount of the organic insulator counterpart, the degree of vanadium oxide ribbons alignment, and the induced porosity reached upon latex removal. Overall, we found out that all the parameters described above and involved within the as-synthesized fibers’ mechanical and sensing properties are acting within a partitive action mode rather than a cooperative one. Introduction Syntheses over “all length scales” 1 and/or bioinspired approaches 2 were proposed around 10 years ago by Ozin and Mann, respectively, to promote complex and multiscale architectures. To reach such complex architectures with an idea of “rational design” it seems important to combine several domains of research, i.e., chemistry (inorganic, organic, polymeric, and hybrid), biology, physical chemistry of complex fluids. From this transdisciplinary approach has emerged a new transversal concept of “integrative chemis- try”, 3 offering thus a versatile tool box where the communi- ties mentioned above will find specific items to compose their own synthetic pathway to reach specific functionalities occurring at diverse length scales. Integrative chemistry has been already applied by combining general chemistry with foams, 4 emulsions, 5 lyotropic mesophases, 6 biologic poly- mer, 7 three-dimensional colloid opal-like textures, 8 and so forth. To the previous set of texturing modes that mostly regard the areas of either soft matter, biology, or supramo- lecular chemistry we might associate inorganic polymeriza- tion occurring under mild or soft conditions. At that stage, “soft chemistry”, 9 and more precisely the sol-gel process, 10 appears as the inorganic chemistry candidate of choice to both promote the inorganic connectivity while not destroying either the supramolecular template used at the mesoscale or the metastable thermodynamic systems imposed at the macroscopic length scale. Among inorganic oxide polymers obtained through the use of the sol-gel chemistry, vanadium oxide is of strong interest, as it is associated with a wide scope of applications ranging from catalysis to photo- chromism and more. 11 Gels of vanadium oxide can be obtained from sodium metavanadate as inorganic precursor and upon an ion exchange process. The texture of the resulting gels is made of vanadium oxide nanoribbon subunits that depict strong anisotropy 12,10b and allows generating a inorganic liquid crystal associated with a nematic character. 13 We first took benefit of this textural property by aligning the ribbon subunits with the use of an extrusion process, thus * Corresponding author. Phone: 33 (0)5 56 84 56 30. Fax: 33 (0)5 56 84 56 00. E-mail: backov@crpp-bordeaux.cnrs.fr. ² Centre de Recherche Paul Pascal. ‡ Universite ´ Bordeaux-I. § Universite ´ Pierre et Marie Curie. (1) (a) Yang, H.; Kuperman, A.; Coombs, N.; Mamiche-Afara, S.; Ozin, G. A. Nature 1996, 379, 703. (b) Feng, P.; Bu, X.; Stucky, G. D.; Pine, D. J. J. Am. Chem. Soc. 2000, 5, 994. (2) (a) Mann, S. Nature 1988, 332, 119. (b) Archibald, D. D.; Mann, S. Nature 1993, 364, 430. (3) Backov, R. Soft Matter 2006, 2, 452. (4) (a) Carn, F.; Colin, A.; Achard, M.-F.; Deleuze, H.; Backov, R. AdV. Mater. 2004, 16, 140. 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