0000000000277173

AUTHOR

Matthias Janke

showing 3 related works from this author

Mechanically interlocked calix[4]arene dimers display reversible bond breakage under force.

2009

The physics of nanoscopic systems is strongly governed by thermal fluctuations that produce significant deviations from the behaviour of large ensembles1,2. Stretching experiments of single molecules offer a unique way to study fundamental theories of statistical mechanics, as recently shown for the unzipping of RNA hairpins3. Here, we report a molecular design based on oligo calix[4]arene catenanes—calixarene dimers held together by 16 hydrogen bridges—in which loops within the molecules limit how far the calixarene nanocapsules can be separated. This mechanically locked structure tunes the energy landscape of dimers, thus permitting the reversible rupture and rejoining of the individual n…

Models MolecularMacromolecular SubstancesSurface PropertiesBiomedical EngineeringMolecular ConformationThermal fluctuationsBioengineeringNanotechnologyMolecular dynamicsPhenolsCalixareneMaterials TestingMoleculeNanotechnologyGeneral Materials ScienceComputer SimulationElectrical and Electronic EngineeringParticle SizePhysicsHydrogen bondEnergy landscapeStatistical mechanicsPhysicistCondensed Matter PhysicsAtomic and Molecular Physics and OpticsNanostructuresModels ChemicalChemical physicsStress MechanicalCalixarenesCrystallizationDimerizationNature nanotechnology
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Self-Assembled Polymers Based on bis-Tetra-Urea Calix[4]arenes Connected via the Wide Rim

2008

Six double calixarenes were synthesised in which two tetra-urea calix[4]arenes are linked by a rigid spacer between the urea functions at their wide rim. The dimerisation of their tetra-urea parts leads to hydrogen-bonded polymeric assemblies in apolar solvents. The addition of the stoichiometric amount of a tetra-tosylurea calix[4]arene disrupts the polymeric structures due to the preferred formation of heterodimeric capsules between tetra-aryl and tetra-tosylurea calix[4]arenes. The existence of polymeric assemblies was further established by AFM studies on spin-coated samples.

chemistry.chemical_classificationbiologyChemistryHydrogen bondGeneral ChemistryPolymerNuclear magnetic resonance spectroscopybiology.organism_classificationchemistry.chemical_compoundPolymer chemistryCalixareneUreaTetraOrganic chemistrySelf-assemblyStoichiometrySupramolecular Chemistry
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Control of CaCO3 Crystallization by Demixing of Monolayers

2006

In this paper we describe how to template a demixed monolayer into a spatially patterned inorganic replica. For this purpose a new amphiphilic monomer was synthesized which can be polymerized both in solution and in the monolayer of a Langmuir-Blodgett (LB) trough. Since it inhibits the crystallization of CaCO3, it can be used--in combination with stearic acid (nucleation-promotor)--to control CaCO3 crystals formed under the monolayer. Investigations of the two-component monolayer (Langmuir isotherms and AFM measurements of transferred films) show--in the biphasic region--demixing in solid analogue stearic acid domains and the liquid analogue phase of the monomer. Crystallization of CaCO3 s…

Surface PropertiesAcrylic ResinsCrystal growthSurfaces and InterfacesCondensed Matter PhysicsLipidsCalcium Carbonatelaw.inventionchemistry.chemical_compoundMonomerchemistryChemical engineeringlawPhase (matter)MonolayerSaturated fatty acidElectrochemistryOrganic chemistryGeneral Materials ScienceStearic acidCrystallizationCrystallizationStearic AcidsSpectroscopyAcrylic acidLangmuir
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