Phase diagram of polyelectrolyte solutions

Kaji, Koichi; Urakawa, Hiroshi; Kanaya, Toshiji; Kitamaru, Ryozo

doi:10.1051/jphys:01988004906099300

Cited by 128 publications

(134 citation statements)

References 15 publications

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“…33,37 Because the studied DNA and HA have rather long chain lengths, in the micrometer range, the corresponding dilute-semidilute crossover concentrations are expected to be several orders of magnitude below the concentration range we studied. 14,17 Thus, these samples are certainly in the semidilute regime. We denote them as long DNA or HA.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

“…Indeed, as expected for semidilute solutions, q m scales with concentration as c 1/2 for both HA and DNA. 14,20,25 FCS. In Figure 7 we present D 110* exp , the diffusion coefficient of DNA110* polyion in various conditions.…”

Section: Saxsmentioning

confidence: 99%

“…The latter is related to c, the monomer concentration − c p = c/N and thus d = (c/N) −1/3 . 14,17,25 Dilute−Semidilute Crossover Concentration. As the polyelectrolyte concentration is raised, the average distance gets reduced and eventually becomes comparable to the chain size or the contour length of the polyion, d ≈ L c .…”

Section: ■ Appendix Amentioning

confidence: 99%

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Probing the Mesh Formed by the Semirigid Polyelectrolytes

et al. 2013

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ABSTRACT:We correlate conformation and dynamics of the semirigid polyelectrolytes deoxyribonucleic acid (DNA) and hyaluronic acid (HA) in the semidilute regime, across a broad concentration range (10 −3 − 10 2 g/L). Salt-free polyelectrolytes are distinct from uncharged polymers as they presumably form a rather rigid, isotropic mesh. The polyelectrolyte characteristic mesh size is known as de Gennes correlation length ξ. We directly probed the mesh formed by DNA and HA, by employing fluorescence correlation spectroscopy (FCS) to measure the diffusion coefficient of fluorescently labeled DNA fragments added in trace amounts. For the salt-free solutions we found that the DNA or HA mesh size has to be 2−3 times larger than the fragments for them to start to diffuse freely (as if in the dilute solution). For a tighter mesh (concentrations 0.1−1 g/L), the fragment diffusion coefficient is only half the free diffusion value. Conversely, fragments show the free diffusion coefficientas if there is no meshin DNA or HA in 10 mM buffer. This complies well with the fact that the ξ fades for polyelectrolytes with added salt. The diffusion coefficient falls off further when the mesh size gets smaller than the fragment size (above 1 g/L) and a similar value is reached in buffer as well as in pure water, respectively, at the highest measured concentrations (10 g/L). We also performed small-angle X-ray scattering (SAXS) on HA and DNA (range 3−130 g/L) to complement our previous dielectric spectroscopy (DS) studies (range 0.01−5 g/L). Combined, these methods provide reference values of the de Gennes length ξ across the range studied by FCS.

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Section: ■ Experimental Methodsmentioning

confidence: 99%

Section: Saxsmentioning

confidence: 99%

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Probing the Mesh Formed by the Semirigid Polyelectrolytes

et al. 2013

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“…Although some improvements can be made by addressing composition fluctuations [9,10] and monomer architecture [11][12][13], the presence of long-ranged forces due to charges and dipoles on the chain backbone makes the extension of the FloryHuggins theory nontrivial. For polymeric systems with ionizable monomers, theories based on field-theoretic treatments [14][15][16][17][18][19][20] have borne out to be successful in treating the phase behavior [21][22][23][24]. When the repeat groups of the polymer chains carry permanent dipoles, theoretical formulation becomes technically difficult primarily due to the anisotropy of the intersegment orientational interactions and due to its long-range nature.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Phase Segregation Induced by Dipolar Interactions in Polymer Blends

Kumar¹,

Sumpter²,

Muthukumar

2014

Macromolecules

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We present a generalized theory for studying phase separation in blends of polymers containing dipoles on their backbone. The theory is used to construct co-existence curves and to study the effects of dipolar interactions on interfacial tension for a planar interface between the coexisting phases. We show that a mismatch in monomeric dipole moments, or equivalently a mismatch in the dielectric constant of the pure components, leads to destabilization of the homogeneous phase. Corrections to the Flory-Huggins phase diagram are predicted using the theory. Furthermore, we show that the interfacial tension increases with an increase in the mismatch of the dipole moments of the components. Density profiles and interfacial tensions are constructed for diffuse and sharp polymer-polymer interfaces by extending the formalisms of Cahn-Hilliard and Helfand-Tagami-Sapse, respectively.

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“…When PSS concentration is less than the critical value causing chain overlapping, PSS chain stays straight and individually like a rod due to the molecular rigidity. 17 The critical concentration for PSS chain overlapping is 1 mg/mL, 18 where PSS chains are separated from each other by charge repulsion and stretched directionally due to the molecular rigidity. In this work, the PSS concentration was tuned to less than 1 mg/mL, and each PSS chain stays straight without overlapping.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Two-Dimensional PEDOT:PSS Nanosheets Through In Situ Formed Complexes

Zhang

Wang

2015

NANO

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This paper presents a simple and e®ective method to fabricate water-soluble two-dimensional (2D) conductive poly(3,4-ethylenedioxythiophene):poly (sodium 4-styrenesulfonate) (PEDOT: PSS) nanosheets. Linear PSS is water-soluble and exhibits a quasi 1D structure in the dilute solution. Addition of 3,4-ethylenedioxythiophene (EDOT) monomers into acidic solutions would form 2D molecular complexes due to charge attraction. In situ polymerization of the ethylenedioxythiophene monomers produces 2D poly EDOT nanosheets. Both transmission electron microscopy and atomic force microscopy characterizations have con¯rmed the 2D polymeric nanosheets. Further Fourier transform infrared (FTIR) characterization also validated that the 2D nanosheet is composed of EDOT-based units and Raman spectroscopy indicated the strong interactions between ethylenedioxythiophene units in the 2D nanostructures. The electrical conductivity is measured to as high as 551.58 S/m for the thin¯lm of as-produced 2D PEDOT: PSS nanosheets.

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Phase diagram of polyelectrolyte solutions

Cited by 128 publications

References 15 publications

Probing the Mesh Formed by the Semirigid Polyelectrolytes

Probing the Mesh Formed by the Semirigid Polyelectrolytes

Enhanced Phase Segregation Induced by Dipolar Interactions in Polymer Blends

Fabrication of Two-Dimensional PEDOT:PSS Nanosheets Through In Situ Formed Complexes

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