Search results for "Mono"
showing 10 items of 6843 documents
Polymeric monolayers and liposomes as models for biomembranes. How to bridge the gap between polymer science and membrane biology?
1984
This contribution deals with the stabilization of membrane model systems, especially vesicles. The desired further biological functionalization of these stabilized polymeric membranes is possible via the incorporation of proteins. Addition of natural lipids to polymerizable membranes and degradation of the unpolymerized component after polymerization allows selective opening of otherwise stable compartments. Finally, first attempts are made to combine biological properties of natural cells and the durability of polymerized membranes via fusion of synthetic vesicles with natural cells.
Effect of phosphatydylcholine on spectral properties and photostability of 3,3′-diethyloxadicarbocyanine iodide (DODCI) — a potent anti-tumor photose…
1998
Abstract The potential anti-tumor photosensitizer 3,3′-diethyloxadicarbocyanine iodide (DODCI) has been immobilized in dimyristoyl phosphatidylcholine (DMPC) vesicles. Binding of the dicarbocyanine to the lipid vesicles induces several changes in the electronic absorption, emission and excitation spectra of the dye. The monomeric dye molecules exist in at least two forms when immobilized in the DMPC liposomes and the non-luminescing H-aggregates of the dye show efficient excitation energy transfer to the DODCI monomers. Entrapment of the dye in the liposomes generally decreases the photostability of DODCI. While emission from singlet oxygen (1O2) has not been recorded, indirect results sugg…
Langmuir–Blodgett films based on inorganic molecular complexes with magnetic or optical properties
2005
Langmuir and Langmuir–Blodgett (LB) films of a great variety of molecular metal complexes with interesting magnetic or optical properties have been prepared in the last few years. Some of the results obtained by our group and others are summarized in this article. (i) LB films of polyoxometalates (POM) were first prepared taking advantage of the adsorption properties of these cluster anions along a positively charged monolayer of an organic surfactant spread in water. A correct choice of the POM allowed the preparation of LB films with magnetic, electrochromic, or luminescent properties. Besides this semiamphiphilic method, two new methods to prepare LB films of POMs have been developed by …
Symmetric naphthalenediimidequaterthiophenes for electropolymerized electrochromic thin films
2015
A new symmetric naphthalenediimidequaterthiophene (s-NDI2ODT4) was synthesized and exhibited the capability to electropolymerize alone or with EDOT affording polymers with controlled donor/acceptor monomer ratios. s-NDI2ODT4-EDOT-based copolymers showed low band gaps, wide optical absorption ranges extending to the near IR region, tuned electrical properties, thin-film surface morphology and hydrophilicity as well as high coloration efficiency in electrochromic devices.
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…
Homocoupling of terminal alkynes on calcite (10.4)
2018
Abstract On-surface synthesis has been identified as highly versatile strategy to prepare molecular structures on surfaces with single-atom precision. Inspired by the classical Glaser coupling, homocoupling of terminal alkynes has attracted great attention for on-surface synthesis. This coupling is known for providing a rigid and linear linkage, which is highly interesting for the synthesis of molecular wires. For molecular wire formation, non-conductive substrates are needed for electronic decoupling. So far, however, coupling of terminal alkynes has not been performed on a bulk insulator surface. Here, we present an atomic force microscopy study, indicating that 4,4″-diethynyl-[1,1′:4′,1″…
Micropatterning of neurons using organic substrates in culture
1997
Abstract In this study, we have used spatially defined surfaces of organic thin films to micropattern the outgrowth of central nervous system neurons in culture. Glass substrates were first chemically modified with synthetic peptides derived from an extra-cellular matrix protein laminin to couple a functionality that promotes a neuron-substrate interaction. The modification procedure was verified using X-ray photoelectron spectroscopy. The functionality of the modified glass surfaces was examined by growing neurons dissociated from mammalian central nervous tissues in culture. Spatially defined surfaces of the peptide were then fabricated by selectively attaching the peptide to coplanar sur…
The effect of pre-heating on monomer elution from bulk-fill resin composites
2020
Background The present study was aimed to evaluate the effect of pre-heating of bulk -fill resin composites on monomer elution from them. Material and Methods Three different types of resin composites were used including Tetric N-Ceram Bulk Fill, X-tra Fill and X-tra Base. 10 cylindrical samples were prepared from each resin composites. Before light curing, 5 samples were pre-heated until reaching 68˚C, then 5 other samples were polymerized at room temperature. After 24 hours, release of UDMA, TEGDMA and BIS-GMA monomers were measured by High-Performance Liquid Chromatography analysis. Data analysis was performed by two-way ANOVA test, Games-Howell and Sidak post hoc tests. Results Pre-heat…
Self-organization of amphiphilic N-acylated linear polyethyleneimines: investigation of a reversible monolayer collapse
1996
Abstract Poly-N-4-decyloxybenzoylethyleneimine, highly crystalline in bulk, forms a stable monolayer at the air-water interface which undergoes a reversible collapse into a probable bilayer structure at higher surface pressures. We achieved transfer both from the monolayer and “bilayer” region of the polymer film at the water surface onto hydrophilic and hydrophobized quartz supports. Based on X-ray investigations on the deposited Langmuir-Blodgett films, a possible mechanism for the reversible collapse is proposed.
Polyreactions in ordered systems: Polymerization of octadecyl methacrylate in monolayers at the gas–water interface
1977
The ultraviolet-initiated polymerization of octadecyl methacrylate (ODMA, octadecyl 2-methyl-2-propenoate) as a monomolecular layer at the gas-water interface was studied. The polymerization was carried out at 27°C at the nitrogen-water interface; air inhibits the polymerization. At 27°C the ODMA monolayer exhibits three different states which were characterized by surface pressure-area diagrams and by surface potential measurements. The ODMA monolayer was polymerized under constant surface pressure in the range between 0 and 10 dyne/cm. The polymerization was followed by recording the contraction of the film. The conversion was determined by comparison of the area per monomer unit during p…