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Liquid-glass transition in charge-stabilized colloidal dispersions

 

作者: S. K. Lai,   G. F. Wang,   W. P. Peng,  

 

期刊: AIP Conference Proceedings  (AIP Available online 1900)
卷期: Volume 519, issue 1  

页码: 99-110

 

ISSN:0094-243X

 

年代: 1900

 

DOI:10.1063/1.1291526

 

出版商: AIP

 

数据来源: AIP

 

摘要:

We model the inter-colloidal interactions in a charge-stabilized colloidal dispersion by a hard-core Yukawa potential&fgr;(r)=&sgr;0&ggr;&hthinsp;exp(−&kgr;r)/r,r>&sgr;0and apply the rescaled mean spherical approximation to calculate its static structure factor. In conjunction with the idealized mode-coupling theory, we determine the loci of the liquid-glass transition phase boundary for a salt-free suspension of charged colloids evaluated at different counter-ion environment (characterized by the &kgr;) in terms of the macro-ion parameters: volume fraction &eegr;, chargeZ0and size&sgr;0.The calculated parametric phase diagrams are quite general since the results, with slight and straightforward modification, can be utilized to study the glass transition in a more realistic colloidal solution such as an aqueous monodisperse suspension of polystyrene charged spheres with an added electrolyte. Confining our discussion, then, to the simplest salt-free colloidal liquids, we extract from our analysis of the calculated liquid-glass transition boundaries some succinct features. Specifically, we show in this work that given a range of interaction&Vkgr;=&kgr;&sgr;0≲3.8,there is a possibility of observing theliquid&lrhar2;glass&lrhar2;liquid&lrhar2;glass(LGLG)re-entrant phenomenon in restrictive regions of the phase diagram&eegr;-&sgr;0or&eegr;-Z0for a monodisperse charge-stabilized solution. However, as the&sgr;0increases above a critical size, the LGLG re-entrant behavior vanishes. To delve into this re-entrant phenomenon, we compare, for a given &Vkgr;, the glassy Debye-Waller factor, static structure factor and their spatial counterparts for two cases—nnone for lower-Z0colloids at a high &eegr; and the other for higher-Z0colloids at a low &eegr;. For the former, the glassification is basically driven by the geometric restriction while that, for the latter, it is mainly induced by the Coulomb force. We conclude from this comparison that under the same screening environment both the excluded volume and the electrostatic effects are equally effective in impelling a charge-stabilized colloidal dispersion to undergo a structural arrest configuration and hence the liquid-glass transition. ©2000 American Institute of Physics.

 

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