Long-range Attraction between Like-charged Colloids: Simulations and Microgravity Experiments
نویسندگان
چکیده
Deionized dilute charged colloidal systems exhibit gas-liquid and gas-solid coexistence and re-entrant transitions depending on suspensions parameters such as volume fraction, charge density and ionic strength. These observations constitute evidence for the existence of long-range attraction between like-charged colloids. Monte Carlo (MC) simulations using Sogami-Ise pair-potential, which has a long-range attractive term, could explain the above mentioned experimental observations. MC simulations, which correspond to zero gravity conditions, revealed coexistence of liquid-like droplet with rare phase (gas-like) and voids coexisting with dense (solid-like) phase clusters. These predictions will be verified by the project of microgravity experiments in space and the outcome is expected to provide evidence for the existence of long-range attraction between like charged colloids. Keyword(s): Charged Colloids, Long-range attraction, Simulations, Light Scattering, Confocal microscopy, Microgravity experiments. Received 12 Feb. 2015, accepted 24 Mar. 2015, published 31 Apr. 2015
منابع مشابه
Polydispersity and gelation in concentrated colloids with competing interactions.
In colloids with competing short-range attractions and long-range repulsions, microcrystalline gels are experimentally formed under conditions where computer simulations point to a lamellar phase as the ground state. Here, upon applying a low-frequency alternating electric field, we bring the system from an initial gel state to a columnar-like state. While molecular dynamics simulations on mono...
متن کاملStrong attraction between charged spheres due to metastable ionized states
We report a mechanism which can lead to long-range attractions between like-charged spherical macroions, stemming from the existence of metastable ionized states. We show that the ground state of a single highly charged colloid plus a few excess counterions is overcharged. For the case of two highly charged macroions in their neutralizing divalent counterion solution we demonstrate that, in the...
متن کاملElectrolyte-Mediated Assembly of Charged Nanoparticles.
Solutions at high salt concentrations are used to crystallize or segregate charged colloids, including proteins and polyelectrolytes via a complex mechanism referred to as "salting-out". Here, we combine small-angle X-ray scattering (SAXS), molecular dynamics (MD) simulations, and liquid-state theory to show that salting-out is a long-range interaction, which is controlled by electrolyte concen...
متن کاملInteraction between like-charged colloidal spheres in electrolyte solutions.
How colloidal particles interact with each other is one of the key issues that determines our ability to interpret experimental results for phase transitions in colloidal dispersions and our ability to apply colloid science to various industrial processes. The long-accepted theories for answering this question have been challenged by results from recent experiments. Herein we show from Monte-Ca...
متن کاملGround State of two Unlike Charged Colloids: An Analogy with Ionic Bonding
In this letter, we study the ground state of two spherical macroions of identical radius, but asymmetric bare charge (QA > QB). Electroneutrality of the system is insured by the presence of the surrounding divalent counterions. Using Molecular Dynamics simulations within the framework of the primitive model, we show that the ground state of such a system consists of an overcharged and an underc...
متن کامل