scholarly journals Critical adsorption of multiple polyelectrolytes onto a nanosphere: splitting the adsorption–desorption transition boundary

2020 ◽  
Vol 17 (167) ◽  
pp. 20200199 ◽  
Author(s):  
Daniel L. Z. Caetano ◽  
Sidney J. de Carvalho ◽  
Ralf Metzler ◽  
Andrey G. Cherstvy
Keyword(s):  
Phase Separation ◽  
Surface Charge Density ◽  
Globular Proteins ◽  
Spherical Nanoparticles ◽  
Separation Curve ◽  
Low Salt ◽  
Electrostatic Binding ◽  
Adsorption Desorption ◽  
Oppositely Charged ◽  
Added Salt

Employing extensive Monte Carlo computer simulations, we investigate in detail the properties of multichain adsorption of charged flexible polyelectrolytes (PEs) onto oppositely charged spherical nanoparticles (SNPs). We quantify the conditions of critical adsorption—the phase-separation curve between the adsorbed and desorbed states of the PEs—as a function of the SNP surface-charge density and the concentration of added salt. We study the degree of fluctuations of the PE–SNP electrostatic binding energy, which we use to quantify the emergence of the phase subtransitions, including a series of partially adsorbed PE configurations. We demonstrate how the phase-separation adsorption–desorption boundary shifts and splits into multiple subtransitions at low-salt conditions, thereby generalizing and extending the results for critical adsorption of a single PE onto the SNP. The current findings are relevant for finite concentrations of PEs around the attracting SNP, such as the conditions for PE adsorption onto globular proteins carrying opposite electric charges.

Surfactant Impurities Can Explain the Jones-Ray Effect

2018 ◽  
Author(s):  
Timothy Duignan ◽  
Marcel Baer ◽  
Christopher Mundy
Keyword(s):  
Surface Tension ◽  
Electrostatic Potential ◽  
Driving Forces ◽  
Salt Water ◽  
Fundamental Property ◽  
Apparent Contradiction ◽  
Low Salt ◽  
Air Water Interface ◽  
Added Salt ◽  
Effect Of Surface

<div> <p> </p><div> <div> <div> <p>The surface tension of dilute salt water is a fundamental property that is crucial to understanding the complexity of many aqueous phase processes. Small ions are known to be repelled from the air-water surface leading to an increase in the surface tension in accordance with the Gibbs adsorption isotherm. The Jones-Ray effect refers to the observation that at extremely low salt concentration the surface tension decreases in apparent contradiction with thermodynamics. Determining the mechanism that is responsible for this Jones-Ray effect is important for theoretically predicting the distribution of ions near surfaces. Here we show that this surface tension decrease can be explained by surfactant impurities in water that create a substantial negative electrostatic potential at the air-water interface. This potential strongly attracts positive cations in water to the interface lowering the surface tension and thus explaining the signature of the Jones-Ray effect. At higher salt concentrations, this electrostatic potential is screened by the added salt reducing the magnitude of this effect. The effect of surface curvature on this behavior is also examined and the implications for unexplained bubble phenomena is discussed. This work suggests that the purity standards for water may be inadequate and that the interactions between ions with background impurities are important to incorporate into our understanding of the driving forces that give rise to the speciation of ions at interfaces. </p> </div> </div> </div> </div>

Aggregation, gelation and phase separation of heat denatured globular proteins

2002 ◽  
Vol 304 (1-2) ◽  
pp. 253-265 ◽  
Author(s):  
Dominique Durand ◽  
Jean Christophe Gimel ◽  
Taco Nicolai
Keyword(s):  
Phase Separation ◽  
Globular Proteins

scholarly journals Sequence Grammar Underlying Unfolding and Phase Separation of Globular Proteins

2021 ◽  
Author(s):  
Kiersten M. Ruff ◽  
Yoon Hee Choi ◽  
Dezerae Cox ◽  
Angelique R. Ormsby ◽  
Yoochan Myung ◽  
...  
Keyword(s):  
Phase Separation ◽  
Globular Proteins

A simple simulation model for complex coacervates

Soft Matter ◽  
2021 ◽  
Author(s):  
Sai Vineeth Bobbili ◽  
Scott Milner
Keyword(s):  
Phase Diagram ◽  
Aqueous Solution ◽  
Phase Separation ◽  
Simulation Model ◽  
Simple Simulation ◽  
The Impact ◽  
Oppositely Charged

When oppositely charged polyelectrolytes mix in an aqueous solution, associative phase separation gives rise to coacervates. Experiments reveal the phase diagram for such coacervates, and determine the impact of charge...

scholarly journals Ionic polypeptide tags for protein phase separation

2019 ◽  
Vol 10 (9) ◽  
pp. 2700-2707 ◽  
Author(s):  
Rachel A. Kapelner ◽  
Allie C. Obermeyer
Keyword(s):  
Phase Separation ◽  
Globular Proteins ◽  
Complex Coacervation ◽  
Protein Activity ◽  
Physiological Conditions

Short ionic polypeptide tags were demonstrated to drive complex coacervation of globular proteins at physiological conditions while maintaining protein activity.

scholarly journals Phase Separation in Symmetric Mixtures of Oppositely Charged Rodlike Polyelectrolytes

2010 ◽  
Vol 114 (31) ◽  
pp. 9956-9976 ◽  
Author(s):  
Rajeev Kumar ◽  
Debra Audus ◽  
Glenn H. Fredrickson
Keyword(s):  
Phase Separation ◽  
Oppositely Charged

Control of osmotic pressure through CO2-capture and release facilitated by the lower critical solution temperature (LCST) phase transition of acylated branched polyethylenimine

RSC Advances ◽  
2016 ◽  
Vol 6 (32) ◽  
pp. 26526-26530 ◽  
Author(s):  
Jeongseon Park ◽  
Minwoo Noh ◽  
Min Keun Chey ◽  
Yeongbong Mok ◽  
Ji-Hun Seo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Separation ◽  
Osmotic Pressure ◽  
Co2 Capture ◽  
Low Temperatures ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Low Salt ◽  
Branched Polyethylenimine ◽  
Capture And Release

A solution of acylated polyethylenimine absorbs CO2 at low temperatures and draws water from high-salt saline due to the high osmotic pressure, while it liberates CO2 after phase separation by mild heating and releases water into low-salt saline.

Electrostatic Interactions and Aqueous Two-Phase Separation Modes of Aqueous Mixed Oppositely Charged Surfactants System

2012 ◽  
Vol 116 (34) ◽  
pp. 10330-10341 ◽  
Author(s):  
Li-Sheng Hao ◽  
Yuan-Xiang Gui ◽  
Yan-Mei Chen ◽  
Shao-Qing He ◽  
Yan-Qing Nan ◽  
...  
Keyword(s):  
Phase Separation ◽  
Electrostatic Interactions ◽  
Two Phase ◽  
Oppositely Charged
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