http://experimentationlab.berkeley.edu/sites/default/files/AFMImages/butt_AFM.pdf

Force measurements with the atomic force microscope: Technique, interpretation and applications

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

http://cds.cern.ch/record/503806/files/0106045.pdf

New developments in the Casimir effect

In this review, initial microbial adhesive interactions are divided into adhesion to substratum surfaces, coaggregation between microbial pairs and co-adhesion between sessile and planktonic microorganisms of different strains or species. The physico-chemical mechanisms underlying the adhesive interactions are described and a critical review is given of currently employed methods to study microbial adhesive interactions, with an emphasis on the use of the parallel plate flow chamber. Subsequently, for each of the three microbial adhesive interactions distinguished, the role of Lifshitz-van der Waals, acid-base and electrostatic interactions is described based on existing literature.

Physico-chemistry of initial microbial adhesive interactions – its mechanisms and methods for study

Data on the experimental structure of small particles is reviewed, the emphasis being an attempt to correlate experimental information with theoretical models. First, a general discussion of some of the controlling factors is presented, primarily equilibrium shapes of small particles, the effect of surface stresses, kinetics, and the role of chemisorption and the substrate. Experimental techniques for obtaining information about small particles are then described, primarily electron microscopy approaches. Experimental data on the static structure of small particles is then reviewed, both single crystals and the many, complicated twinned structures in face-centred cubic materials. An overview is then given of some of the more recent results on dynamic phenomena in small particles. Finally, a general model merging thermodynamic and kinetic factors is presented to attempt to rationalize the available data, followed by a brief discussion.

Experimental studies of small particle structures

The surface force interactions between individual 8 μm diameter spheres and atomically flat substrates have been investigated using atomic force techniques The lift-off force of glass, polystyrene, and tin particles from atomically smooth mica and highly oriented pyrolitic graphite substrates was determined as a function of the applied loading force in an inert nitrogen environment While the relative magnitudes of the measured lift-off force were found to scale as expected between the various systems studied, the absolute values were a factor of ∼50 smaller than expected from the Johnson, Kendall, and Roberts theory The surface topography of representative spheres was characterized with atomic force microscopy, allowing a quantitative assessment of the role that surface roughness plays in the adhesion of micrometer-size particles to substrates Taking into account the radius of curvature of the asperities measured from the atomic force scans, agreement between the measured and theoretical estimates for

Surface roughness and its influence on particle adhesion using atomic force techniques

The interaction force gradient between a micron-size polystyrene sphere and an atomically flat highly oriented pyrolytic graphite substrate has been analyzed as a function of surface-to-surface separation distance ${\mathit{z}}_{0}$ using an oscillating cantilever technique. The interaction force gradient was found to have two contributions. For ${\mathit{z}}_{0}$\ensuremath{\ge}30 nm, an electrostatic force due to charges trapped on the polystyrene sphere dominates. For ${\mathit{z}}_{0}$\ensuremath{\le}30 nm, a van der Waals interaction, characteristic of a sphere near a flat plane, is observed. Fits to the data are in good agreement with theoretical expectations and allow estimates of the surface charge density triboelectrically produced on the sphere's surface. \textcopyright{} 1996 The American Physical Society.

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Identification of electrostatic and van der waals interaction forces between a micrometer-size sphere and a flat substrate

The adhesion of particles to surfaces is accompanied by deformations of the materials arising from adhesion force-induced stresses. These deformations, which can be the result of an elastic, a nonlinear elastic, a viscoelastic, or a plastic response of the materials to the stresses, can significantly affect the forces needed to remove the particles from the substrate. The mechanics of adhesion-induced deformations between micrometer-size particles and various substrates are discussed in this paper. Examples of elastic and plastic deformations resulting from the adhesion forces are presented. The experimental results are analyzed in terms of various adhesion theories, which, under certain circumstances, permit the calculation of the thermodynamic work of adhesion for contacting solids. The ranges of validity of these theories and their predictions are discussed. Finally, adhesion-induced deformations which are not currently explicable in terms of these theories are presented.

Mechanics of particle adhesion

A small particle toner image is formed on a primary image member (1), such as a photoconductor, and electrostatically transferred to an intermediate image member (2) and then electrostatically transferred to a receiving sheet. The intermediate image member is chosen to have characteristics making the toner less attractive to the primary image number, but more attractive to the receiving sheet than the intermediate. The intermediate transfer member can include a base (30) of a relatively compliant material having a Young's modulus 107 Newtons per square meter or less with a very thin outer skin (20) of a harder material having a Young's modulus of 5x107 Newtons per square meter or more.

Intermediate transfer method and roller

Disclosed is an improved method of non-electrostatically transferring dry toner particles which comprise a toner binder and which have a particle size of less than 8 micrometers from an element to a receiver. The receiver comprises a substrate having a coating of a thermoplastic polymer thereon and a layer of a releasing agent on the coating, where the polymer has a Tg less than 10° C. above the Tg of the toner binder, and the release agent is present in an amount sufficient to prevent the polymer from adhering to the element. The receiver is heated to a temperature such that its temperature during transfer is above the Tg of the polymer.

Donald S. Rimai

Papers

Surface roughness and its influence on particle adhesion using atomic force techniques

Identification of electrostatic and van der waals interaction forces between a micrometer-size sphere and a flat substrate

Mechanics of particle adhesion

Intermediate transfer method and roller

Method of non-electrostatically transferring toner