Ladnorg, T.

Wöll, C.

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Fabrication and Characterization ofMetal-Organic Frameworks (MOFs)Thin FilmsTatjana Ladnorg, Christof WöllInstitute for Functional SurfacesSurface ScienceTatjana.Ladnorg@kit.eduMetal-Organic FrameworksMetal-organic frameworks (MOFs) consistof organic ligands linked together by metalions. They belong to a relatively new classof highly ordered porous materials. Theinterest in obtaining thin films of metal-organic frameworks, has increased in thelast decade because of their high surfacearea.The dimension of pores is given by the lengths of organic ligands and can bedifferent depending on the MOF.4500 m /g2+The MOF-5 structure consists of a cubic array ofZn O(CO ) units connected by phenylene links.4 2 6Literature: GasAdsorption Sites in a Large-Pore Metal-Organic FrameworkJesse L. C. Rowsell,1 Elinor C. Spencer,2 Juergen Eckert,3,4JudithA. K. Howard,2 Omar M. Yaghi1*Growth of MOF thin films on surfacesThe of these MOF materials (SURMOFs) is a key step, which is considered crucial for applications in the field ofnanotechnology, ranging from hydrogen and other energy storage to the delivery of therapeutic agents in medicine and themanufacturing of sensor devices.growth on surfaces0 2 4 6 8 10-100102030405060Height[nm]Position [µm]Figure 5:In this diagrammthe dimension of MOFgrowth is shown bythe analysis with theAFM.a) The fractaldimensionb) The texturedirection indexFigure 1: The surface area of the size of onesugar cube is equal to the area of half of a footballfieldFigure 3: For the growth of SURMOFs on surfaces it is necessary to have a well ordered self-assembled monolayer (SAM) with the right functional head-group as abasis for it. In this case µCP was used to pre-pattern the surface with an active SAM and then incubate in a second SAM which is inactive.In order to grow theSURMOF selectivly on the active SAM.a) b)In this case the Eu-MOF linkers are fluorescent. Withthe combination of an invers fluorescence microscopeand an AFM it is possible to detect the fluorescenceat the wavelenght of ~300cm in addition to thetopgography.-1AcknowledgementsSpecial thanks to Dr. R. Heck andDr. O. Shekhah for the support and thecontribution on this study.Figure 6: AFM image zoom of Figure 4 for roughnessanalysis.Data you can define out of thisAFM image are for example:Sa 6,15 nmSq 7,75 nmSsk 0.867Sku 4.26Sy 64.4 nmRoughness averageRoot mean square (RMS).The Root Mean Square Gradient is the RMS - value of the surface slopewithin the sampling area.The Surface Skewness describes the asymmetry of the height distributionhistogram.The Surface Kurtosis describes the "peakedness" of the surfacetopography.They are defined as the height difference between the highest and lowest pixelin the image.Sz 53.2    nmb)a)Analysis with an AFM, correlated with an fluorescent inverse microscopeµCP was used to laterally pre-pattern the surface in order to study the selective growth of MOF which allows determining therate of SURMOF growth.Figure 7:Fluorescence of theEU-MOF and theAFMFigure 2: Structure of MOF-5 unit cellMOFFunctionalized SAMNot functionalized SAMSiliconwafer coverd with gold andtitaniumFigure 4: a) AFM image (height mode) of an Eu-MOFselectivly grown in 10 layers on a µCP pre-patterned surface withactive mercaptohexadecanoic acidb) Height profile of the MOFand inactivehexadecanethiol

Fabrication and characterization of metal-organic frameworks (MOFs)

https://publikationen.bibliothek.kit.edu/220081119/3815778

Fabrication and characterization of metal-organic frameworks (MOFs)

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