Zeta potential adhesion

In various kinds of industrial production, materials need to be treated with charged colloidal particles. In such systems, the value of the zeta-potential analyses are needed to control production. For example, in paper, adhesive, and synthetic plastics, colloidal clay can be used as filler. In oil drilling, clay colloidal suspensions are used. The zeta potential is controlled so as to avoid clogging the pumping process in the oil well. It has been found that, for instance, the viscosity of a clay suspension shows a minimum when the zeta potential is changed (with the help of pH from 1 to 7) from 15 to 35 mV. Similar observations have been reported in coal slurry viscosity. The viscosity was controlled by the zeta potential. 

Kaolin [1332-58-7] - [CERAMICS-OVERVIEW] (Vol 5) - [ALUMINUMCOMPOUNDS - INTRODUCTION] (Vol2) - [DENTAL MATERIALS] (Vol 7) -as adhesive filler [ADHESIVES] (Vol 1) -aluminumchloride [ALUMINUMCOMPOUNDS - ALUMINUMHALIDESAND ALUMINUMNITRATE] (Vol2) -as release agent [RELEASE AGENTS] (Vol 21) -zeta potential [DISPERSANTS] (Vol 8)... 

Kirby, B.J., Wheeler, A.R., Zare, R.N., Fruetel, J.A., Shepodd, T.J., Programmable modification of cell adhesion and zeta potential in silica microchips. Labchip 2003, 3, 5-10. 

Huang YC, Fowkes FM, Loyd TB (1991) Acidic and basic nature of ferric oxide surfaces. Adsorption, adhesion, zeta potential and dispersibility in magnetic inks for hard disks. In Mittal KL, Anderson HR (eds) Acid-Base-Interactions. VSP Utrecht, p 363... 

The largest adhesion force of alumina particles in DI water was attributed to a stronger electrostatic attraction between alumina particles and copper surface in DI water owing to their opposite signs of zeta potentials. The smallest adhesion force of alumina particles in the citric acid slurry was attributed to the... 

The frictional and adhesion forces between the abrasive particles and wafer surfaces were experimentally measured using alumina and silica slurries with and without citric acid. Although citric acid did not affect the zeta potential of the silica particles, it resulted in a more negative zeta potential of the alumina particles due to the adsorption of the negatively charged citrate ions onto the alumina surfaces. The highest particle adhesion force was measured in an alumina slurry without the addition of citric acid. However, the alumina slurry with the addition of citric acid had the lowest particle adhesion force due to the adsorption of citrate ions onto the alumina surfaces. Although citrate ions could easily adsorb onto alumina particles, the silica particles did not appear to benefit in terms of reduced frictional force when in citric acid solutions. 

Lindberg, R. et al.. Studies of adhesion of metal particles to sihca particles based on zeta potential measurements, J. Dispersion Sci. Technol., 20, 715, 1999. 

When the zeta-potential equals zero, fast flocculation stage prevails and the probability of collision-adhesion of particles increases. In addition, the effect of electrolytes is also small. 

Clearly, cells will be attracted to surfaces of opposite zeta potential. If cells have the same zeta potential as a surface, attachment is still possible provided the electrostatic barrier can be penetrated by small surface projections (van Oss et al, 1 8 Grinnell, ). Zeta potentials and the adhesion of microbes have been reviewed by Daniels (27), Martin (28), and Marshall (29). 

These considerations lead to the conclusion that a rational approach to.problems of the adhesion of cells to solid surfaces can be developed from knowledge of the surface properties of both the substrate and the cell. Solid surface energies can be obtained by measurements of contact angles and use of Neumann s equation (Eq. 6), thus allowing calculations of free energy charges associated with adhesion. Zeta potentials and resultant electrostatic contributions to adhesion can also be obtained experimentally. This type of approach should provide insight into microbial adhesion problems in the marine and aquatic environments, disease and infection and in the industrial immobilization of whole cells. 

Zeta potential also serves for determination of isoelectric point (lEP), which is defined as the point at which the electrokinetic potential equals zero. It is also important characteristic for wrappers, for material for study of living cell adhesion, etc. Fig. 3 present zeta potential of several polymer foils as pH dependent. As it is clear, lEP of all polymer samples are obtained at pH ca 4. For this determination we have titrated samples by 0.1 mol/dm HCl in pH range from 7.0 to 2.5 [52]. 

As it is clear from Fig. 8, plasma treatment leads to increase of zeta potential due to creation of more polar groups on surface and this effect depends on exposure time positively. Subsequent grafting of PEG influences surface chemistry dependently on its molecular weight. While PEG 300 and PEG 20000 in most cases causes a slight decrease of zeta potential, PEG 6000 for shorter exposure time causes increase of zeta potential. It indicates quite different surface chemistry and nevertheless these changes are quiet slight, they play important role in process of adhesion and proliferation of living cells (see Fig. 9). 

The zeta-potential is frequently used to predict the stability of a suspension or the adhesion of suspended particles on macroscopic surfaces (e.g. cellulose fibres, tubing). This is because double layer interaction between particles or between particles and surfaces is governed by the ion distribution in the diffuse layer, which primarily depends on the Debye-Hiickel parameter k and the diffuse layer potential i/ d- The latter, however, is commonly approximated by the zeta potential f (Lyklema 2010, cf. Fig. 3.3). It is quite obvious that repulsion requires high zeta-potential values of equal sign, whereas adhesion occurs in the absence of surface charge or for oppositely charged surfaces. 

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