TEMPO-mediated oxidation of microgranular cellulose results in particles of three different length scales: cellulose nanocrystals as well as small (μm) and larger (tens of μm) porous particles with high charge density.

An antimicrobial peptide, Magainin I (Mag), was grafted to a titanium oxide surface, via an antiadhesive poly(ethylene glycol) (PEG) cross-linker. The latter plays a 2-fold part, being antiadhesive, and enabling the covalent immobilization of the peptide. The functionalization was characterized at each step by reflection absorption infrared spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS). The antiadhesive properties of PEG, and antibacterial activity of the anchored Magainin I, were individually tested toward adsorption of bovin serum albumin (BSA) proteins, and against Gram positive bacteria, Listeria ivanovii , respectively. The results reveal that adhesion of both proteins and bacteria have been considerably reduced, accompanied by an inhibition of the growth of remaining adhered bacteria. This work thus offers a novel approach to functionalize oxide surfaces against biofilms and to measure the so-obtained properties in each of the successive steps of a biofilm formation.

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Nitrocarburising is a thermochemical diffusion treatment involving the surface nitrogen enrichment of low alloyed steels, leading to the formation of iron carbonitrides characterised by good tribological properties. In order to make engineering components multi-functional, new processes including post-operations have been developed in the last decade but their influence on corrosion resistance is not yet fully understood. The aim of the present study is to determine the corrosion behaviour of gas nitrocarburised steel produced on both a laboratory and industrial scale. Behaviour has been evaluated by salt spray tests as well as by electrochemical techniques (corrosion potential and polarisation resistance evolutions versus immersion time, potentiodynamic curves). All nitrocarburising treatment improves the corrosion resistance compared to untreated steel. Post-oxidising treatments have no significant influence on corrosion resistance but an impregnation step appears efficient in enhancing corrosion. The carbonitrides present in the ‘white layer’ are nobler than the substrate, and promote localised corrosion through open porosity of the outlayer by a galvanic effect.

The surface self-assembly properties of acidic sophorolipids, a bolaform microbial glycolipids with pHresponsive properties in solution, were studied based on the chemical nature of the support and pH of the solution. Sophorolipids generally form micelles in water but formation of morphologies like platelets and twisted fibers depending on pH have also been reported. The surface self-assembly was achieved using dip-coating on three different substrates namely gold, silicon(111) and TiO 2 anatase. Deposition conditions (dip-coating withdrawal speed, relative humidity, temperature) were tested, and it was found that optimum self-assembly occurred at a withdrawal speed of 1 mm s À1 , T of 25 1C and relative humidity of 25%. The local structure of the sophorolipid films was characterized by Atomic Force Microscopy, while Scanning Electron Microscopy was used to characterize the spatial homogeneity. We also attempted to correlate dispersive, electron donor and electron attractor surface energy components, using Good-Van Oss's approach, and the behavior of sophorolipids. We found that when the surface energy is dominated by dispersive components, sophorolipids spontaneously assemble into entangled needles at all pH values (4, 6 and 11). However, when the surface energy is dominated by electronic components, pH has a strong influence on the surface self-assembly. We could discriminate three major organizations: homogeneous layer, isolated aggregates and a two-dimensional network similar to block copolymer surface self-assembly.

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