生物矿化与仿生材料Biomim10_Langmuir.pptVIP

From Biomineralization to Biomimetic Materials Chemistry:Synthesis under Langmuir Films Last lecture: Analysis of FAP-mineralization in collagen internal fields, core-shell assembly, organic matrix Literature: B. Heywood, S. Mann ?Template-directed nucleation and growth of inorganic materials“ Adv.Mater. 6 (1994) 9. Today: 1st biologically inspired materials synthesis application of artificially modified surfaces Langmuir-films preparation and properties of Langmuir films (Langmuir-Blodgett-Films) mineralization under Langmuir films Repetition: Interfacial Molecular Recognition in Nature Periodic arrangement of -COOH -groups as template for inorganic phase Langmuir-Films Periodic arrangement of hydrophilic head-groups at gas-liquid interface Preparation of Langmuir-films Experimental setup: CPBD: barrier device compresses film at surface self-organization to monolayer measurement of pressure by ?Wilhelmy-balance“ ?-A Plot Excursion:Langmuir-Blodgett-Films Preparation of Langmuir-film: Immersion of hydrophilic substrate: monolayer of amphiphil is transferred to polar surface surface is now unpolar repetition of procedure... Repetition: Polymorphism of CaCO3- Calcite and Aragonite Polymorphs of CaCO3:calcite and aragonite Projections of (001)-plane Mineralisation of Calcite 1 Conditions: Amphiphil: long-chain carbonic acid [Ca++] 10 mM Mineralisation of Calcite 2 Monolayers: vertical arrangement of molecules viewed from above: hexagonal packing Theoretical calculations: Distance of head groups (5?) corresponds with distance between CO32- of calcite (4,96 ?) in (1-1.0)-plane Mineralisation of Calcite 3 Conditions: Amphiphil: Eicosyl-sulfate ?tridentate“ template nucleation (00.1)-plane Mineralisation of Aragonite Conditions: presence of Mg++ “Overgrowth” of seeds by needles fast growth in solution Mineralisation of Vaterite Conditions: “Inverse polarity” due to use of amines as amphiphiles mineralization does barely depend on conditions in solution S