No abstract

No abstract

Abstract. 2014 The modification of the graphite surface after weak oxidation using a nitric acid solution has been studied by X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). A new corrugation at the atomic scale has been revealed by STM on the basal planes. It is attributed to the presence, in other respects demonstrated by XPS, of some oxygenated groups created by oxidation and regularly distributed on the surface. This soft oxidation conserves the graphite basal planes and is interpreted by an oxygen chemisorption on graphite through a bond involving 03C0 electrons of the aromatic cell. Organic groups which need dangling 03C3 bonds to fix on the surface should preferencially attach on ridges of large defects.Microsc. Microanal. Microstruct. 5 (1994)

The ordering and adhesion of latex particles on model inorganic surfaces are investigated through atomic force microscopy. The particles are made of a soft polymeric core protected by a hydrophilic membrane made of carboxylic acids, and they are dispersed in water. This dispersion is spread on model inorganic surfaces. After water evaporation, there is a monolayer of rather well dispersed particles on the substrate. The measured particle heights are dependent on the scanning rate and on the force of the probe tip acting on the sample. Below the polymer glass temperature, the particles have weak adhesion to the surface and are moved easily by the probe tip. This results in tip-induced organization of the particles. The analysis of particle profiles shows that, above glass temperature, there is a sudden and partial spreading of the particles which is governed by the polymeric chain mobility and not by capillary forces. The particle adhesion and spreading ratio are controlled by acid-base interactions between latex particles and the surface. IntroductionSynthetic latices consist of colloidally-dispersed polymer particles which can be prepared by a tightly-controlled emulsion polymerization technique. These aqueous dispersions are commonly used as binders for inorganic pigments in a wide range of applications that include paints, adhesives, paper coating, and carpet backing.l Most

No abstract