Modulation of colloidal forces with polyampholytes
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The stability of a colloidal solution consisting of a mixture of charged spherical aggregates and polyampholytes is investigated by means of Monte Carlo simulations. The double-layer repulsion between the charged macroions is reduced upon addition of neutral polyampholyte and for sufficiently highly charged colloids it is converted into a net attractive interaction. Attractive interactions can also be created between macroions with polyampholytes that have a net charge of the same sign as the macroion. The mechanism for the attractive interactions is the same as for charged aggregates destabilized by oppositely charged polyelectrolytes; that is, a chain adsorbs to two macroions forming a bridge between them. Strictly alternating polyampholytes give rise to a weak attractive component, while chains with larger blocks of alternating positive and negative monomers are efficient destabilizers. The destabilizing action can qualitatively be correlated with the chain polarizability. The linear polarizability accounts for the behavior in weakly charged dispersions, while higher order polarizabilities seem to play a key role in solutions with more highly charged aggregates.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Publication status||Published - 2002|
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Theoretical Chemistry (S) (011001039)