Model of aggregation of colloidal fine particles in the presence of supersized polymer

A simple model of the process of stabilization and destabilization of fine colloidal suspensions induced by supersized linear polymers has been tested by the direct simulation method. In the model, a single polymer molecule may bind a number of colloidal particles and thus form an aggregate. It is assumed that a simultaneous attachment of a few fine particles to one macromolecule does not necessarily destabilize the suspension. The destabilization of the system (occurring if aggregate sedimentation dominates its diffusion ability) takes place only when the number of the attached particles per macromolecule exceeds the critical value which depends on the polymer coil dimension in the dispersion medium. The model permits interpretation of several experimental observations of the behavior of colloidal sols upon introduction of very high molecularweight polymers. The simulation results have been compared with the experimental data on the effect of polyacrylamide on the stability of AgI sol.

[1]  J. A. V. BUTLER,et al.  Theory of the Stability of Lyophobic Colloids , 1948, Nature.

[2]  G. J. Fleer,et al.  Kinetic aspects of polymer bridging: equilibrium flocculation and nonequilibrium flocculation. , 1989 .

[3]  B. Cabane,et al.  Growth of colloidal aggregates through polymer bridging , 1993 .

[4]  G. J. Fleer,et al.  Kinetics of bridging flocculation. Role of relaxations in the polymer layer , 1990 .

[5]  S. Redner,et al.  Fluctuation effects in Smoluchowski reaction kinetics , 1984 .

[6]  K. Wong,et al.  Intermediate structures in equilibrium flocculation , 1992 .

[7]  F. Hesselink.  Density distribution of segments of a terminally adsorbed macromolecule , 1969 .

[8]  S. Edwards.  The theory of polymer solutions at intermediate concentration , 1966 .

[9]  Richard G. Brereton,et al.  Statistical Methods in Applied Chemistry , 1990 .

[10]  Y. Otsubo.  Effect of particle size on the bridging structure and elastic properties of flocculated suspensions , 1992 .

[11]  Y. Otsubo.  Size effects on the shear‐thickening behavior of suspensions flocculated by polymer bridging , 1993 .

[12]  R Hogg,et al.  Collision efficiency factors for polymer flocculation , 1984 .

[13]  A model of flocculation by very-high-molecular-weight polymers , 1989 .

[14]  Z. Shou,et al.  Polymer adsorption on fine particles; the effects of particle size and its stability , 1992 .

[15]  Daniel ben-Avraham,et al.  Computer simulation methods for diffusion‐controlled reactions , 1988 .

[16]  E. Dickinson,et al.  Computer simulation of bridging flocculation , 1991 .

[17]  V. K. Mer.  Filtration of colloidal dispersions flocculated by anionic and cationic polyelectrolytes , 1966 .

[18]  W. Graessley.  Polymer chain dimensions and the dependence of viscoelastic properties on concentration, molecular weight and solvent power , 1980 .

[19]  W. Walles.  Role of flocculant molecular weight in the coagulation of suspensions , 1968 .

[20]  B. Moudgil,et al.  Collision efficiency factors in polymer flocculation of fine particles , 1987 .

[21]  P. Pincus,et al.  Properties of polymer layers adsorbed on surfaces under nonequilibrium conditions , 1989 .

[22]  R. Kniewske,et al.  Preparation, characterization, solution properties and rheological behaviour of polyacrylamide , 1982 .