Refine
Year of publication
Document Type
- Article (90)
- Postprint (12)
- Doctoral Thesis (2)
- Other (2)
- Conference Proceeding (1)
Keywords
- Leguminosae (3)
- HDAC1 (2)
- RUNX2 (2)
- atomic force microscopy (2)
- biomaterials (2)
- calcium influx (2)
- mesenchymal stem cells (2)
- polymer (2)
- reversible shape-memory actuator (2)
- (S)-Elatadihydrochalcone (1)
- (S)-Lupinifolin 4´-methyl ether (1)
- AC -Impedance (1)
- AC Impedanz (1)
- Amphiphiles (1)
- Anserine (1)
- Anti-HIV (1)
- Antimalarial drug detection (1)
- Antiplasmodial activity (1)
- Artemisinin (1)
- Asteraceae (1)
- Biomolecules coupling (1)
- Biophysical chemistry (1)
- Bragg coherent x-ray diffractive imaging (1)
- Derris trifoliata (1)
- Diode laser (1)
- Dual scale factors (1)
- Electro-synthesized molecularly imprinted polymer (1)
- Electrochemical impedance (1)
- Electrochemical sensor (1)
- Enzymes (1)
- Festelektrolyten (1)
- Flavanone (1)
- Functional groups (1)
- Functionalization (1)
- Galactosides (1)
- Gel polymer (1)
- Glycoconjugates (1)
- Glycopeptides (1)
- Graphene derivates (1)
- Graphene oxide (1)
- InP nanowires (1)
- Interfacial capacitance (1)
- Ion exchange (1)
- Ionic conductivity (1)
- Ionic selectivity (1)
- Isotope detection (1)
- JH-III-specific carrier protein (1)
- Juvenile hormone (1)
- Leptinotarsa decemlineata (1)
- Lithium ion battery (1)
- Lithium-Ionen-Batterie (1)
- Lupinifolin (1)
- Matrix IR spectrum (1)
- Molecular biophysics (1)
- Near infrared (1)
- OH suppression (1)
- Polarization elements (1)
- Polylactide stereocomplex (1)
- Porous (1)
- RGD-peptide (1)
- SAXS (1)
- SQM-FF (1)
- Seedpods (1)
- Senecio roseiflorus (1)
- Steroid esters (1)
- Surface exudates (1)
- Tautomerism (1)
- Tephrosia elata (1)
- Tephrosia subtriflora (1)
- Wavelength modulation gas spectroscopy (1)
- X-ray crystallography (1)
- [N]phenylene dyads (1)
- [N]phenylenes (1)
- actuation (1)
- antiplasmodial (1)
- astrophotonics (1)
- atmospheric effects (1)
- bilayer (1)
- biodiversity (1)
- blend (1)
- cardiovascular disease (1)
- cardiovascular implant (1)
- chain-extended (1)
- common species (1)
- copper-catalyzed alkyne-azide cycloaddition (1)
- cyclic thermomechanical testing (1)
- cytotoxicity (1)
- density functional calculations (1)
- diffractive elements (1)
- dissociative electron attachment (1)
- drug discovery (1)
- ecosystem function (1)
- electrically switchable gratings. (1)
- electrospinning (1)
- enantioselectivity (1)
- fiber meshes (1)
- fibre Bragg gratings (1)
- gas-phase reactions (1)
- gemini surfactant (1)
- hemocompatibility (1)
- identity hypothesis (1)
- infrared: general (1)
- instrumentation: miscellaneous (1)
- ionic liquids (1)
- ionische Flüssigkeiten (1)
- land use (1)
- materials science (1)
- microparticles (1)
- miscibility (1)
- morphology (1)
- multitrophic (1)
- nanostructure (1)
- o-Phenylenediamine (1)
- on demand particle release (1)
- ordering process (1)
- photoinduced electron transfer (1)
- platelets (1)
- polarization gratings (1)
- polycaprolactone (1)
- polymer surface (1)
- polymer/LC composites (1)
- prenylated flavanonol (1)
- reversible shape-memory effect (1)
- sensitizers (1)
- shape-memory effect (1)
- shape-memory polymers (1)
- side-chains functionalization (1)
- soft matter micro- and nanowires (1)
- solid-state-electrolyte (1)
- spectroscopy (1)
- strain field (1)
- subtriflavanonol (1)
- switchable retarder (1)
- temperature-memory effect (1)
- thermosensitive (1)
- β-Hydroxydihydrochalcone (1)
Institute
- Institut für Chemie (107) (remove)
SAXS/WAXS studies were performed in combination with freeze fracture electron microscopy using mixtures of a new Gemini catanionic surfactant (Gem 16-12, formed by two sugar groups bound by a hydrocarbon spacer with 12 carbons and two 16-carbon chains) and the zwitterionic phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine(DPPC) to establish the phase diagram. Gem 16-12 in water forms bilayers with the same amount of hydration water as DPPC. A frozen interdigitated phase with a low hydration number is observed below room temperature. The kinetics of the formation of this crystalline phase is very slow. Above the chain melting temperature, multilayered vesicles are formed. Mixing with DPPC produces mixed bilayers above the corresponding chain melting temperature. At room temperature, partially lamellar aggregates with local nematic order are observed. Splitting of infinite lamellae into discs is linked to immiscibility in frozen state. The ordering process is always accompanied by dehydration of the system. As a consequence, an unusual order-disorder phase transition upon cooling is observed.
Recent calculations on the hydrogen-exchange reaction [Bouakline et al., J. Chem. Phys. 128, 124322 (2008)], have found strong geometric phase (GP) effects in the state-to-state differential cross-sections (DCS), at energies above the energetic minimum of the conical intersection (CI) seam, which cancel out in the integral cross-sections (ICS). In this article, we explain the origin of this cancellation and make other predictions about the nature of the reaction mechanisms at these high energies by carrying out quasiclassical trajectory (QCT) calculations. Detailed comparisons are made with the quantum results by splitting the quantum and the QCT cross-sections into contributions from reaction paths that wind in different senses around the CI and that scatter the products in the nearside and farside directions. Reaction paths that traverse one transition state (1-TS) scatter their products in just the nearside direction, whereas paths that traverse two transition states (2-TS) scatter in both the nearside and farside directions. However, the nearside 2-TS products scatter into a different region of angular phase-space than the 1-TS products, which explains why the GP effects cancel out in the ICS. Analysis of the QCT results also suggests that two separate reaction mechanisms may be responsible for the 2-TS scattering at high energies.
When a hydrogen (H) atom approaches a deuterium (D-2) molecule, the minimum-energy path is for the three nuclei to line up. Consequently, nearly collinear collisions cause HD reaction products to be backscattered with low rotational excitation, whereas more glancing collisions yield sideways-scattered HD products with higher rotational excitation. Here we report that measured cross sections for the H + D-2 -> HD(v' = 4, j') + D reaction at a collision energy of 1.97 electron volts contradict this behavior. The anomalous angular distributions match closely fully quantum mechanical calculations, and for the most part quasiclassical trajectory calculations. As the energy available in product recoil is reduced, a rotational barrier to reaction cuts off contributions from glancing collisions, causing high-j' HD products to become backward scattered.
We report a combined directing effect of the simultaneously applied graphoepitaxy and electric field on the self-assembly of cylinder forming polystyrene-b-poly(dimethylsiloxane) block copolymer in thin films. A correlation length of up to 20 mu m of uniaxial ordered striped patterns is an order of magnitude greater than that produced by either graphoepitaxy or electric field alignment alone and is achieved at reduced annealing times. The angle between the electric field direction and the topographic guides as well as the dimensions of the trenches affected both the quality of the ordering and the direction of the orientation of cylindrical domains: parallel or perpendicular to the topographic features. We quantified the interplay between the electric field and the geometry of the topographic structures by constructing the phase diagram of microdomain orientation. This combined approach allows the fabrication of highly ordered block copolymer structures using macroscopically prepatterned photolithographic substrates.
Electric field manipulated nanopatterns in thin films of metalorganic 3-miktoarm star terpolymers
(2016)
We report the effect of electric field on the morphological transitions and ordering behavior of polyferrocenylethylmethylsilane block (PFEMS)-containing copolymers. By analyzing structures in solvent-annealed films of metalorganic sphere-and cylinder-forming diblock copolymers, as well as of 3-miktoarm polyisoprene-arm-polystyrene-arm-PFEMS (3 mu-ISF) terpolymers, we decouple two types of responses to the electric field: morphological transformations as a result of an increase in the volume fraction of the PFEMS block by oxidation of the ferrocenyl groups, and the orientation of the dielectric interfaces of microdomains parallel to the electric field vector. In the case of 3m-ISF, the former effect dominates at high electric field strengths which results in an unexpected cylinder-to-sphere transition, leading to a well-ordered hexagonal dot pattern. Our results demonstrate multiple tunability of ordered microdomain morphologies, suggesting future applications in nanofabrication and surface patterning.
Time- and temperature-resolved in situ birefringence measurements were applied to analyze the effect of nanoparticles on the electric field-induced alignment of a microphase separated solution of poly(styrene)-block-poly(isoprene) in toluene. Through the incorporation of isoprene-confined CdSe quantum dots the reorientation behavior is altered. Particle loading lowers the order-disorder transition temperature, and increases the defect density, favoring nucleation and growth as an alignment mechanism over rotation of grains. The temperature dependent alteration in the reorientation mechanism is analyzed via a combination of birefringence and synchrotron SAXS. The detailed understanding of the effect of nanoparticles on the reorientation mechanism is an important prerequisite for optimization of electricfield-induced alignment of block copolymer/nanoparticle composites where the block copolymer guides the nanoparticle self-assembly into anisotropic structures.
New mesoporous silk fibroin (SF)/silica hybrids were processed via a one-pot soft and energy-efficient sol-gel chemistry and self-assembly from a silica precursor, an acidic or basic catalyst, and the ionic liquid 1-butyl-3-methylimidazolium chloride, acting as both solvent and mesoporosity-inducer. The as-prepared materials were obtained as slightly transparent-opaque, amorphous monoliths, easily transformed into powders, and stable up to ca. 300 degrees C. Structural data suggest the formation of a hexagonal mesostructure with low range order and apparent surface areas, pore volumes, and pore radii of 205-263 m(2) g(-1), 0.16-0.19 cm(3) g(-1), and 1.2-1.6 nm, respectively. In all samples, the dominating conformation of the SF chains is the beta-sheet. Cytotoxicity/bioactivity resazurin assays and fluorescence microscopy demonstrate the high viability of MC3T3 pre-osteoblasts to indirect (>= 99 +/- 9%) and direct (78 +/- 2 to 99 +/- 13%) contact with the SF/silica materials. Considering their properties and further improvements, these systems are promising candidates to be explored in bone tissue engineering. They also offer excellent prospects as electrolytes for solid-state electrochemical devices, in particular for fuel cells.