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TiO 2 Sphere‐Tube‐Fiber Transition Induced by Oligovaline Concentration Variation
Author(s) -
Mantion Alexandre,
Taubert Andreas
Publication year - 2007
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.200600192
Subject(s) - calcination , fiber , chemistry , chemical engineering , nanoscopic scale , crystallography , polymer chemistry , materials science , diffraction , micrometer , template , nanotechnology , organic chemistry , optics , catalysis , engineering , physics
L ‐Valine‐based oligopeptides with the general structure Z‐( L ‐Val) n ‐OMe or OH ( n = 1–4) form stable organogels in a variety of solvents, including the inorganic liquid tetraethylorthosilicate. The acid form Z‐( L ‐Val) n ‐OH is a less efficient gelator than the methyl ester, but forms stable organogels in aromatic solvents and di‐ and trichloromethane. In all cases the peptides form micrometer long helical fibers with a β ‐sheet structure. IR and X‐ray diffraction show that the peptides have closely related structures in the crystalline state and the fibers in the organogels. The gels are efficient templates for the fabrication of complex titania architectures on a (sub)micron length scale: at low peptide concentrations titania spheres form and at higher concentrations one‐dimensional shapes like hollow titania tubes or titania fibers are observed. The tubes are stable towards calcination whereas the fibers (partially) transform into spherical or even bulk particles.