Charge and salt-driven reentrant order-disorder and gas-solid transitions in charged colloids

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:264

Article

Mohanty, PS ; Tata, BVR

关键词: charged colloidal suspensions;    effect of charge density;    reentrant order-disorder transition;    long-range attraction;    Monte Carlo simulations;    pair-correlation function;    gas-solid transition;    homogeneous-to-inhomogeneous transition;   

DOI  :  10.1016/S0021-9797(03)00368-0

来源: Elsevier

【 摘 要 】

Monte Carlo simulations have been performed for aqueous charged colloidal suspensions as a function of effective charge density (sigma) on the particles and salt concentration C-s. We vary the effective charge density in our simulations over a range where a reentrant solid-liquid transition in suspensions of silica and polymer latex particles has been reported by Yamanaka et al. (Phys. Rev. Lett. 80 (1998) 5806). We show that at low ionic strengths a homogeneous liquid-like ordered suspension undergoes crystallization upon increasing a. Further increase in er resulted once again in a disordered state, which is in agreement with experimental observations. In addition to this reentrant order-disorder transition, we observe an inhomogeneous-to-homogeneous transition in our simulations when salt is added to the disordered inhomogeneous state. This inhomogeneous-to-homogeneous disordered transition is analogous to the solid-gas transition of atomic systems and has not yet been observed in charged colloids. The reported experimental observations on charged colloidal suspensions are discussed in the light of present simulation results. (C) 2003 Elsevier Inc. All rights reserved.

【 授权许可】

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