Hierarchically structured vanadium pentoxide-polymer hybrid materials.
Biomimetic composite materials consisting of vanadium pentoxide (V2O5) and a liquid crystal (LC) "gluing" polymer were manufactured exhibiting six structural levels of hierarchy, formed through LC phases. The organic matrix was a polyoxazoline with pendant cholesteryl and carboxyl units, forming a lyotropic phase with the same structural orientation extending up to hundreds of micrometers upon shearing, and binding to V2O5 via hydrogen bridges. Composites consisting of V2O5-LC polymer hybrid fibers with a pronounced layered structuring were obtained. The V2O5-LC polymer hybrid fibers consist of aligned V2O5 ribbons, composed of self-assembled V2O5 sheets, encasing a chiral nematic polymer matrix. The structures of the V2O5-LC polymer composites strongly depend on the preparation method, i.e., the phase-transfer method from aqueous to organic medium, in which the polymer forms LC phases. Notably, highly defined micro- and nanostructures were obtained when initiating the synthesis using V2O5 tactoids with preoriented nanoparticle building units, even when using isotropic V2O5 dispersions. Shear-induced hierarchical structuring of the composites was observed, as characterized from the millimeter and micrometer down to the nanometer length scales using complementary optical and electron microscopy, SAXS, μCT, and mechanical nanoindentation.
Physical Chemistry, University of Konstanz , Universitätsstraße 10, D-78457 Konstanz, Germany.
Ulrich
U
Tritschler
Igor
I
Zlotnikov
Paul
P
Zaslansky
Peter
P
Fratzl
Helmut
H
Schlaad
Helmut
H
Cölfen
D015097:3-Mercaptopropionic Acid / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry; D032701:Biomimetics; D002784:Cholesterol / Q000031:analogs & derivatives / Q000737:chemistry; D003460:Crystallization; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D055095:Optics and Photonics; D010777:Photochemistry; D011108:Polymers / Q000737:chemistry*; D012542:Scattering, Radiation; D053838:Scattering, Small Angle; D033081:Shear Strength; D013314:Stress, Mechanical; D017968:Vanadium Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction
D001672:Biocompatible Materials; D011108:Polymers; D017968:Vanadium Compounds; C422409:liquid crystal polymer; C002297:thiocholesterol; D006859:Hydrogen; D002784:Cholesterol; D015097:3-Mercaptopropionic Acid; C066075:vanadium pentoxide