The interplay between screening properties and colloid anisotropy: towards a reliable pair potential for disc-like charged particles.
Eur Phys J E Soft Matter
; 15(4): 345-57, 2004 Dec.
Article
en En
| MEDLINE
| ID: mdl-15570447
ABSTRACT
The electrostatic potential of a highly charged disc (clay platelet) in an electrolyte is investigated in detail. The corresponding non-linear Poisson-Boltzmann (PB) equation is solved numerically, and we show that the far-field behaviour (relevant for colloidal interactions in dilute suspensions) is exactly that obtained within linearized PB theory, with the surface boundary condition of a uniform potential. The latter linear problem is solved by a new semi-analytical procedure and both the potential amplitude (quantified by an effective charge) and potential anisotropy coincide closely within PB and linearized PB, provided the disc bare charge is high enough. This anisotropy remains at all scales; it is encoded in a function that may vary over several orders of magnitude depending on the azimuthal angle under which the disc is seen. The results allow to construct a pair potential for discs interaction, that is strongly orientation dependent.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Coloides
/
Mezclas Complejas
/
Electroquímica
/
Electrólitos
/
Silicatos de Aluminio
/
Modelos Químicos
Tipo de estudio:
Diagnostic_studies
/
Evaluation_studies
/
Screening_studies
Idioma:
En
Revista:
Eur Phys J E Soft Matter
Asunto de la revista:
BIOFISICA
Año:
2004
Tipo del documento:
Article
País de afiliación:
Francia