Nature of Dynamic Friction in a Humid Hydrophobic Nanocontact.

The physics of dynamic friction on water molecule contaminated surfaces is still poorly understood. In line with the growing interest in hydrophobic contact for industrial applications, this paper focuses on friction mechanisms in such interfaces. As a commonly used material, contact with graphite is considered in a twin-fold approach based on experimental investigations using the circular mode atomic force microscopy technique combined with molecular dynamic simulations.

Experimental characterization and micromechanical modeling of the elastic response of the human humerus under bending impact.

This paper investigates the characterization and numerical modeling of the elastic behavior of the human humerus bone using a recently developed micromechanical approach coupled to nanoindentation measurements. At first, standard three-point bending experiments were conducted under low static loading, using several humerus diaphysis in order to identify the apparent elastic modulus of the bone in static regime. Then, a drop tower impact experiment was used on the same set of humerus diaphysis specimens, in order to assess the elastic modulus in dynamic regime.

Exploring wear at the nanoscale with circular mode atomic force microscopy.

The development of atomic force microscopy (AFM) has allowed wear mechanisms to be investigated at the nanometer scale by means of a single asperity contact generated by an AFM tip and an interacting surface. However, the low wear rate at the nanoscale and the thermal drift require fastidious quantitative measurements of the wear volume for determining wear laws. In this paper, we describe a new, effective, experimental methodology based on circular mode AFM, which generates high frequency, circular displacements of the contact.

Photoinitiating Systems Based on Anthraquinone Derivatives: Synthesis of Antifouling and Biocide Coatings.

Photoinitiating systems combining 2,6-diaminoanthraquinone (AQD), iodonium salt (Iod), and benzyl alcohol derivatives have been developed to efficiently initiate the cationic polymerization of epoxy monomers upon light exposure. Electron spin resonance spin-trapping (ESR ST) experiments, fluorescence investigations, and steady-state photolysis have demonstrated that a dye-sensitized reaction occurs between AQD and the benzyl alcohol derivatives through a hydrogen abstraction mechanism upon light illumination, followed by reduction of Iod. The in situ liberation of protic acids promotes the cationic photopolymerization of epoxy monomers concomitantly with hydrolysis and condensation of the reactive methoxysilanes of an organic-inorganic precursor, for example, 3-glycidyloxypropyltrimethoxysilane (GPTMS).