Search results for "Nolay"

Organized assemblies of magnetic clusters

2003

Abstract In this work we have explored the possibilities to create layered organizations of the Mn 12 single-molecule magnets using the Langmuir–Blodgett technique or attaching these clusters onto a metal surface by preparing self-assembled monolayers (SAMs). In the first part we discuss the use of the Langmuir–Blodgett (LB) technique in order to obtain organized magnetic films formed by monolayers of these clusters. Two strategies have been used with this aim. The first one consists of mixing Mn 12 acetate or benzoate derivatives with an amphiphile, while the second procedure is based on the use of Mn 12 derivatives specifically designed to form LB films. An alternative method is that of p…

Microspectroscopy on single domains of phase-separated monolayers

1989

SUMMARY A versatile and inexpensive, but fully equipped apparatus is presented, which enables detailed optical studies on amphiphilic molecules at the liquid-gas interface. Structural and spectroscopic information, particularly in small areas of single domains of phase-separated monolayers, can be achieved by combination of this miniaturized Langmuir trough and spectralphotometer microscope. The potential of this apparatus is demonstrated with some measurements on a diyne-substituted polymerizable lipid analogue at the air-water interface.

Immobilization of functionalized lipids in a random poly(methacrylate) copolymer monolayer

1995

It is shown that a monolayer of random poly(methacrylate) copolymer with a hydrophobic and a hydrophilic substituent exhibits a transition from the fluid to amorphous state. Above this transition any amphiphilic molecules mixed with the monolayer are immobile. Furthermore, such functionalized lipids are immobilized in the monolayer during the Langmuir-Blodgett transfer. The hydrophilic head-groups of the biotin-lipids remain on the formerly water-adjacent side of the monolayer, even if this side is exposed to air

Optical Studies of Amphiphilic Molecules with Interesting Electro-Optical and Non-Linear Optical Properties

1990

Structural control is a major issue in both life science, investigating the function of the biological machinery, and in materials science, aiming at the design of novel devices. In part one, recent electro-optical investigations of the primary event of photosynthesis on purified protein preparations are described. Part two focuses on structural studies of monolayers at an air/water interface, and of Langmuir-Blodgett multilayers from a new molecule designed for nonlinear optical applications.

Monolayers of Amphiphilic Molecules

1992

There are good reasons why the organizers have placed this lecture at the beginning of a conference on the multip1e aspects of membranes. In many respects the monolayer may be considered half of a membrane and it obviously is the most simple and best-defined model system. Yet we will show that the system is more complex than many have anticipated. On the other hand, there are many general features which can be discussed without looking into chemical details.

Ellipsometric study of the physisorption of benzene on graphite

1987

The optical thickness of benzene on the (001) surface of a graphite single crystal has been studied by ellipsometry. Ellipsometric adsorption isotherms have been measured in the temperature range from 180 to 290 K. The maximum thickness of the adsorbed benzene film is constant in this temperature range and compares favourably with the value expected for one monolayer of molecules lying flat on the surface.

Effect of the Mo atom flow on the molybdenum growth on TiO2 (110) surface

2004

Abstract Molybdenum has been deposited at room temperature on stoichiometric TiO 2 (1 1 0) surfaces with two deposition rates: 0.1 equivalent monolayer (eqML) and 1.5 eqML min −1 . X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy studies clearly reveal an effect of the deposition rate upon the growth mode and the interfacial reaction. Indeed, whereas a strong interfacial reaction between Mo and TiO 2 involves a Stranski–Krastanov growth mode with the formation of amorphous molybdenum oxide monolayers for the lowest deposition rate, no reaction can be observed for the highest deposition rate. Moreover in this latter case, the growth mode seems to be a 3D …

2018

We report a novel multi-step method for the preparation of ordered mesoporous titania scaffolds and show an illustrative example of their application to solar cells. The method is based on (monolayer) colloidal nanosphere lithography that makes use of polystyrene nanoparticles organised at a water–air interface and subsequently transferred onto a solid substrate. A titania precursor solution (titanium(IV) isopropoxide in ethanol) is then drop-cast onto the monolayer and left to “incubate” overnight. Surprisingly, instead of the expected inverse monolayer-structure, a subsequent calcination step of the precursor yields an ordered monolayer of hollow titania nanospheres with a wall thickness …

Homogeneous Langmuir-Blodgett Film of Double-Chain Ammonium Amphiphile Complexed with Anionic Polymer

1988

Heterogeneous textures suggesting the coexistence of a fluid and a solid phase were found both in a surface monolayer and in a deposited Langmuir-Blodgett (LB) film of double-chain ammonium amphiphiles by fluorescence microscopy. Although an annealing of the surface monolayer at 40°C allowed crystal growth, the heterogeneous phase separation remained in the LB film. A drastic change of the fluorescence image shows that the recrystallization of the complexed monolayer with anionic polymers conducted the homogeneous monolayer.

Watching adsorption and electron beam induced decomposition on the model system Mo(CO)(6)/Cu(111) by X-ray absorption and photoemission spectroscopies

2013

Abstract An in-depth study of the first steps of electron beam assisted growth of Mo from molybdenum hexacarbonyl on Cu(1 1 1) has been carried out exploiting the complementarity of X-ray photoemission and X-ray absorption spectroscopies. Frank van der Merwe (2D) growth mode has been observed for the completion of the two first monolayers of adsorbed molecules through a simple physisorption process. Irradiation of the Mo(CO)6 deposit by 1 keV electron beam induces a modification of molybdenum coordination, the average number of C-neighbors decreasing from 6 to 3. Decomposed molecules remain on the surface after annealing at 520 K and organize themselves, the molybdenum atoms moving in Cu(1 …