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

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

Colloid mobilization and transport in groundwater

: A distinct sequence of sorption of different bacterial types has been observed both on glass slides and electron microscope grids immersed in seawater for periods of up to 24 hours. A comparison of the bacterial groups initially attracted to a surface with those subsequently adhering firmly to the surface suggests a selective irreversible sorption of certain groups of marine bacteria. Firm adhesion of bacteria in the short time periods considered does not involve pili or holdfast structures. The ability to produce extracellular polymeric fibrils may be important in such selective sorption. Two phases in the process of sorption of marine bacteria to surfaces have been defined as (a) an instantaneous reversible phase, and (b) a time-dependent irreversible phase. Reversible sorption of the non-motile Achromobacter sp. strain R8 decreases to zero as the electrolyte concentration decreases, or as the thickness of the electrical double-layer increases. The electrolyte concentration at which all bacteria are repelled from the glass surface depends on the valency of the electrolyte. The reversible phase of sorption is interpreted in terms of the balance between the electrical double-layer repulsion energies at different electrolyte concentrations and the van der Waals attractive energies. The rotational motion of the motile Pseudomonas sp. strain R3 at a liquid-glass interface is considered in terms of the concept of reversible sorption.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0715376&Location=U2&doc=GetTRDoc.pdf

I. Selective Sorption of Bacteria from Seawater. II. Mechanism of the Initial Events in the Sorption of Marine Bacteria to Surfaces

Summary: The sorption of two marine bacteria to surfaces involved an instantaneous reversible phase, and a time-dependent irreversible phase. Reversible sorption of the non-motile Achromobacter strain R8 decreased to zero as the electrolyte concentration decreased, or as the thickness of the electrical double-layer increased. The electrolyte concentration at which all bacteria were repelled from the glass surface depended on the valency of the cation. The reversible phase is interpreted in terms of the balance between the electrical double-layer repulsion energies at different electrolyte concentrations and the van der Waals attractive energies. Even at the electrolyte concentration of seawater, the bacteria probably are held at a small distance from the glass surface by a repulsion barrier. Reversible sorption often led to rotational motion of the motile Pseudomonas sp. strain R3 at a liquid-glass interface. Pseudomonas R3 produced polymeric fibrils in artificial seawater; these may be concerned in the irreversible sorption of the bacteria to surfaces. Sorption and polymer production were stimulated by 7 mg./l. glucose but higher levels inhibited irreversible sorption. Omission of Ca2+ and Mg2+ from the artificial seawater prevented growth, polymer production, and sorption to surfaces by Pseudomonas R3.

/pdf/mechanism-of-the-initial-events-in-the-sorption-of-marine-1k1kspuxjv.pdf

Mechanism of the Initial Events in the Sorption of Marine Bacteria to Surfaces

http://www.oocities.org/santanuparia/research/pdf/acis-04.pdf

A review on experimental studies of surfactant adsorption at the hydrophilic solid-water interface.

A quantitative theory is presented which describes the kinetics of coagulation of colloidal systems containing more than one dispersed species. A general expression has been derived to describe the potential energy of interaction between dissimilar spherical colloidal particles, using the linear (Debye-Huckel) approximation for low surface potentials. An overall stability ratio has been defined which takes into account the possibility of interactions between like, as well as unlike, particles in the system. The errors introduced by the use of the linear approximation have been assessed in terms of their effects on the stability ratio, and found to be quite small. The theory has been used to describe the behaviour of a hypothetical system under various conditions.

Mutual coagulation of colloidal dispersions

Surfactant Adsorption at the Solid—Liquid Interface—Dependence of Mechanism on Chain Length

The zero-points-of-charge for a series of manganese dioxides have been determined by both electrophoretic and coagulation-sedimentation techniques. The zpc was found to increase from pH 1.5 for the amorphous δ form of MnO 2 up to pH 7.3 for β-MnO 2 , the most well-defined crystalline form. This variation is interpreted in terms of, and is shown to be in agreement with, the electrostatic field strength concept modified to describe more complex solids. The change in cation-anion spacing, as derived from the volume per unit cell per cation in the crystal lattice, corresponds to a change in the polarization of the water dipoles and their subsequent dissociation to establish the electrochemical double layer at the oxide-water interface.

T. W. Healy

Papers

Mutual coagulation of colloidal dispersions

Surfactant Adsorption at the Solid—Liquid Interface—Dependence of Mechanism on Chain Length

The effect of crystal structure on the surface properties of a series of manganese dioxides

The energetics of flocculation and redispersion by polymers

Adsorption of alkylbenzene sulfonate (A.B.S.) surfactants at the alumina-water interface