0000000000061763

AUTHOR

Werner Steffen

showing 6 related works from this author

Ruthenium-Containing Block Copolymer Assemblies: Red-Light-Responsive Metallopolymers with Tunable Nanostructures for Enhanced Cellular Uptake and An…

2015

The use of self-assembled nanostructures consisting of red-light-responsive Ru(II)-containing block copolymers (BCPs) for anticancer phototherapy is demonstrated. Three Ru-containing BCPs with different molecular weights are synthesized. Each BCP contains a hydrophilic poly(ethylene glycol) block and an Ru-containing block. In the Ru-containing block, more than half of the side chains are coordinated with [Ru(2,2':6',2''-terpyridine)(2,2'-biquinoline)](2+) , resulting in more than 40 wt% Ru complex in the BCPs. The Ru complex acts as both a red-light-cleavable moiety and a photoactivated prodrug. Depending on their molecular weights, the BCPs assemble into micelles, vesicles, and large comp…

Materials scienceLightStereochemistryCell SurvivalPolymersBiomedical EngineeringPharmaceutical Sciencechemistry.chemical_element02 engineering and technology010402 general chemistry01 natural sciencesMicelleRutheniumPolyethylene GlycolsBiomaterialschemistry.chemical_compoundNeoplasmsSide chainCopolymerMoietyHumansProdrugsMicellesPhototherapy021001 nanoscience & nanotechnologyCombinatorial chemistry0104 chemical sciencesRutheniumNanostructuresMolecular WeightchemistrySelf-assemblyTerpyridine0210 nano-technologyEthylene glycolHydrophobic and Hydrophilic InteractionsHeLa CellsAdvanced healthcare materials
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Adaptive Wetting-Adaptation in Wetting

2018

Many surfaces reversibly change their structure and interfacial energy upon being in contact with a liquid. Such surfaces adapt to a specific liquid. We propose the first order kinetic model to describe dynamic contact angles of such adaptive surfaces. The model is general and does not refer to a particular adaptation process. The aim of the proposed model is to provide a quantitative description of adaptive wetting and to link changes in contact angles to microscopic adaptation processes. By introducing exponentially relaxing interfacial energies and applying Young's equation locally, we predict a change of advancing and receding contact angles depending on the velocity of the contact line…

chemistry.chemical_classificationMaterials science02 engineering and technologySurfaces and InterfacesPolymerMechanics010402 general chemistry021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesSurface energy0104 chemical sciencesPhysics::Fluid DynamicsCondensed Matter::Soft Condensed MatterContact angleHysteresisAdsorptionchemistryMonolayerElectrochemistryGeneral Materials ScienceWettingDiffusion (business)0210 nano-technologySpectroscopy
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From Spherical Mesopores to Worm-Shaped Mesopores : Morphology Transition in Titania–Polystyrene-b-poly(ethylene oxide) Composite Films with Increasi…

2013

A morphology transition from spherical mesopores to worm-shaped mesopores within titania block copolymer composite thin films has been observed by varying the sol–gel reaction time from 40 min to 48 h in the four-component templating system of polystyrene-$\mathit{b}$-poly(ethylene oxide) (PS-$\mathit{b}$-PEO), 1,4-dioxane, concentrated HCl, and titanium tetraisopropoxide (TTIP) with a PS-$\mathit{b}$-PEO mass concentration of 0.25 wt.-%. The impact of the sol–gel reaction time on the local structure, long-range lateral structure, and vertical structure of the as-prepared, calcined, and UV-degraded thin films as well as the structural changes in solution have been systematically investigate…

ChemieNanotechnologyMicellelaw.inventionInorganic ChemistryX-ray reflectivitychemistry.chemical_compoundDynamic light scatteringchemistryChemical engineeringlawddc:540Grazing-incidence small-angle scatteringCalcinationPolystyreneMesoporous materialSol-gel
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Elastic Superhydrophobic and Photocatalytic Active Films Used as Blood Repellent Dressing.

2020

Durable and biocompatible superhydrophobic surfaces are of significant potential use in biomedical applications. Here, a nonfluorinated, elastic, superhydrophobic film that can be used for medical wound dressings to enhance their hemostasis function is introduced. The film is formed by titanium dioxide nanoparticles, which are chemically crosslinked in a poly(dimethylsiloxane) (PDMS) matrix. The PDMS crosslinks result in large strain elasticity of the film, so that it conforms to deformations of the substrate. The photocatalytic activity of the titanium dioxide provides surfaces with both self-cleaning and antibacterial properties. Facile coating of conventional wound dressings is demonstra…

Materials scienceLightSurface PropertiesComposite filmBiocompatible Materialsmacromolecular substances02 engineering and technologySubstrate (printing)engineering.material010402 general chemistry01 natural sciencesCatalysischemistry.chemical_compoundCoatingMaterials TestingEscherichia coliHumansGeneral Materials ScienceComposite materialElasticity (economics)Escherichia coli InfectionsTitaniumHemostasisMechanical Engineeringtechnology industry and agriculture021001 nanoscience & nanotechnologyBiocompatible materialBandagesElasticity0104 chemical sciencesAnti-Bacterial AgentschemistryMechanics of MaterialsTitanium dioxidePhotocatalysisengineeringNanoparticles0210 nano-technologyScience technology and societyHydrophobic and Hydrophilic InteractionsAdvanced materials (Deerfield Beach, Fla.)
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Morphology evolution in mesoporous titania block copolymer composite films with increasing Sol-Gel reaction time

2013

A morphology evolution of thin films of titania from spherical mesopores to worm-shaped mesopores was realized by simply varying the sol–gel reaction time from 46 min to 25 h in the quadruple system consisting of polystyrene–block-poly(ethylene oxide) (PS–b-PEO), 1,4-dioxane, concentrated HCl, and titanium tetraisopropoxide (TTIP). Imaging techniques including scanning electron microscopy (SEM) and atomic force microscopy (AFM) were applied to investigate the local structure change of the as-prepared, calcined, and UV-degraded composite films. Grazing incidence small angle X-ray scattering (GISAXS) experiments prove that the structure change in local areas is representative of that over the…

Inorganic ChemistryX-ray reflectivityChemical engineeringDynamic light scatteringScanning electron microscopeChemistryComposite numberCopolymerChemieGrazing-incidence small-angle scatteringNanotechnologyMesoporous materialSol-gel
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Phototherapy: Ruthenium-Containing Block Copolymer Assemblies: Red-Light-Responsive Metallopolymers with Tunable Nanostructures for Enhanced Cellular…

2016

0301 basic medicineMaterials scienceNanostructureStimuli responsiveBiomedical EngineeringPharmaceutical Sciencechemistry.chemical_elementNanotechnologyRutheniumBiomaterials03 medical and health sciences030104 developmental biologychemistryDrug deliveryCopolymerSelf-assemblyRed lightAdvanced Healthcare Materials
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