Field‐theoretic simulations of polyelectrolyte complexation

Popov, Yuri O.; Lee, Jonghoon; Fredrickson, Glenn H.

doi:10.1002/polb.21334

Cited by 74 publications

(99 citation statements)

References 51 publications

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“…The model considered in this work is similar to that considered in previous field-theoretic studies of polyelectrolyte systems exhibiting complex coacervation 22,23 with some modifications. For completeness and to highlight some of the differences between our field-theoretic model and previous incarnations of the model, we will recount the model in detail.…”

Section: A Polyelectrolyte Modelmentioning

confidence: 65%

“…One challenge of adopting the field-theoretic approach is that it is a relatively new class of simulation, and therefore the techniques to calculate important material properties (e.g., the interfacial tension ) have not yet been developed. In this study, we extend the previous FTS of complex coacervation 22,23 by characterizing the interfacial properties between the coacervate and the solvent. Density profiles are calculated, and we adapt two techniques from the literature on particle-based simulations to calculate the interfacial tension from fieldtheoretic simulations.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, such an approach has been used to study complex coacervation. 22,23 The phase diagram estimated from RPA was compared to the diagram calculated on the full FTS treatment, and it was shown that in the limit of high polymer concentrations, RPA does a satisfactory job of capturing the fluctuation effects and predicts a qualitatively accurate phase diagram. However, the RPA approach becomes inaccurate for systems with a high charge density, because it overestimates the charge correlations.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the interfacial tension of complex coacervates using field-theoretic simulations

Riggleman

Kumar

Fredrickson

2012

The Journal of Chemical Physics

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Complex coacervation, a liquid-liquid phase separation that occurs when two oppositely charged polyelectrolytes are mixed in a solution, has the potential to be exploited for many emerging applications including wet adhesives and drug delivery vehicles. The ultra-low interfacial tension of coacervate systems against water is critical for such applications, and it would be advantageous if molecular models could be used to characterize how various system properties (e.g., salt concentration) affect the interfacial tension. In this article we use field-theoretic simulations to characterize the interfacial tension between a complex coacervate and its supernatant. After demonstrating that our model is free of ultraviolet divergences (calculated properties converge as the collocation grid is refined), we develop two methods for calculating the interfacial tension from field-theoretic simulations. One method relies on the mechanical interpretation of the interfacial tension as the interfacial pressure, and the second method estimates the change in free energy as the area between the two phases is changed. These are the first calculations of the interfacial tension from full fieldtheoretic simulation of which we are aware, and both the magnitude and scaling behaviors of our calculated interfacial tension agree with recent experiments. Complex coacervation, a liquid-liquid phase separation that occurs when two oppositely charged polyelectrolytes are mixed in a solution, has the potential to be exploited for many emerging applications including wet adhesives and drug delivery vehicles. The ultra-low interfacial tension of coacervate systems against water is critical for such applications, and it would be advantageous if molecular models could be used to characterize how various system properties (e.g., salt concentration) affect the interfacial tension. In this article we use field-theoretic simulations to characterize the interfacial tension between a complex coacervate and its supernatant. After demonstrating that our model is free of ultraviolet divergences (calculated properties converge as the collocation grid is refined), we develop two methods for calculating the interfacial tension from field-theoretic simulations. One method relies on the mechanical interpretation of the interfacial tension as the interfacial pressure, and the second method estimates the change in free energy as the area between the two phases is changed. These are the first calculations of the interfacial tension from full fieldtheoretic simulation of which we are aware, and both the magnitude and scaling behaviors of our calculated interfacial tension agree with recent experiments.

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Section: A Polyelectrolyte Modelmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the interfacial tension of complex coacervates using field-theoretic simulations

Riggleman

Kumar

Fredrickson

2012

The Journal of Chemical Physics

Self Cite

103

130

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“…They used Complex-Langevin simulations to look at fluctuation effects in pure symmetric diblocks. Since then, Fredrickson and coworkers have shown that the method can be extended in various ways, e.g., it can deal with external stresses [225]), and it can be applied very naturally to charged polymers [226,227]. Nevertheless, there are still problems with it.…”

Section: Field-based Modelsmentioning

confidence: 99%

Theory and Simulation of Multiphase Polymer Systems

Schmid

2011

Handbook of Multiphase Polymer Systems

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The theory of multiphase polymer systems has a venerable tradition. The 'classical' theory of polymer demixing, the Flory-Huggins theory, was developed in the 1940s [1,2]. It is still the starting point for most current approaches -be they improved theories for polymer (im)miscibility that take into account the microscopic structure of blends more accurately, or sophisticated field theories that allow to study inhomogeneous multicomponent systems of polymers with arbitrary architectures in arbitrary geometries. In contrast, simulations of multiphase polymer systems are quite young. They are still limited by the fact that one must simulate a large number of large molecules in order to obtain meaningful results. Both powerful computers and smart modeling and simulation approaches are necessary to overcome this problem.In the limited space of this chapter, we can only give a taste of the state-of-the-art in both areas, theory and simulation. Since the theory has reached a fairly mature stage by now, many aspects of it are covered in textbooks on polymer physics [3][4][5][6][7][8][9]. The information on the state-of-the art of simulations is much more scattered. This is why we have put some effort into putting together a representative list of references in this area -which is of course still far from complete.The chapter is organized as follows. In Section II, we briefly introduce some basic concepts of polymer theory. The purpose of this part is to make the chapter accessible to readers who are not very familiar with polymer physics; it can safely be skipped by the others. Section III is devoted to the theory of multiphase polymer systems. We recapitulate the Flory-Huggins theory and introduce in particular the concept of the Flory interaction parameter (the χ parameter), which is a central ingredient in most theoretical descriptions of multicomponent polymer systems. Then we focus on one of the most successful mean-field theories for inhomogeneous (co)polymer blends, the self-consistent field theory. We sketch the main idea, discuss various Handbook of Multiphase Polymer Systems, First Edition. Edited by Abderrahim Boudenne, Laurent Ibos, Yves Candau, and Sabu Thomas.

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“…It is also useful to point out that polyelectrolyte condensation theory remains incomplete and that charged polymers are some of the most difficult systems to study theoretically or by simulations. [16] To address this problem, we examine herein the interactions between poly1 20 and ssDNA by a combination of photoluminescence (PL) spectroscopy, FRET studies and liquid phase AFM. Correlation of optical properties in water with size distributions on a surface provides insight into the correct physical features and structural dynamics of these nanoscalar polyelectrolyte complexes.…”

Section: Introductionmentioning

confidence: 99%

Anatomy and Growth Characteristics of Conjugated Polyelectrolyte/DNA Aggregates

Chworoś

Zhang

Mikhailovsky

et al. 2008

Adv Funct Materials

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Conjugated polyelectrolytes (CPEs) have been widely used as light harvesting macromolecules to amplify the signals of fluorescent assays that betray the presence of various biomolecular targets. Electrostatic interactions play an important role in coordinating optical coupling events and lead to the formation of complexes between oppositely charged CPEs and the target species. Here, we combine for the first time optical studies and structural characterization by liquid phase atomic force microscopy (AFM) to provide a picture of aggregate structure and growth dynamics between cationic CPE and DNA as a function of charge ratio. Specifically, poly120, a copolymer containing a backbone with 50% fluorene, 30% phenylene, and 20% 2,1,3‐benzothiadiazole (BT) units and pendant cationic groups was mixed with single stranded DNA (ssDNA) labeled with the Cy5 acceptor chromophore. Continuous addition of ssDNA‐Cy5 to poly120 leads to a saturation in Cy5 emission due to Cy5–Cy5 self‐quenching. Addition of ssDNA to a preformed poly120/ssDNA‐Cy5 solution results in increased sensitization by energy transfer and a reduction of Cy5–Cy5 self quenching. Adsorption of aggregates onto negatively charged mica under water allows for direct imaging of the polyelectrolyte complexes as a function of charge ratio. The composite set of observations allows for the development of a model for aggregate growth, which is dynamic and ceases when the surface charge becomes sufficiently negative. This saturation point can be mitigated by addition of unlabeled ssDNA.

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Field‐theoretic simulations of polyelectrolyte complexation

Cited by 74 publications

References 51 publications

Investigation of the interfacial tension of complex coacervates using field-theoretic simulations

Investigation of the interfacial tension of complex coacervates using field-theoretic simulations

Theory and Simulation of Multiphase Polymer Systems

Anatomy and Growth Characteristics of Conjugated Polyelectrolyte/DNA Aggregates

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