Mixed brushes consisting of oppositely charged <scp>Y‐shaped</scp> polymers in salt free, monovalent, and divalent salt solutions

Miliou, Kalliopi; Gergidis, Leonidas N.; Vlahos, Costas

doi:10.1002/pol.20200141

Cited by 5 publications

(12 citation statements)

References 39 publications

(58 reference statements)

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“…In addition to the electrostatic interactions, bead‐bead interactions were considered in order to mimic the macroscopic solvent conditions. These interactions are calculated using a truncated Lennard‐Jones potential 25,26 :

U_{LJ} ((), r_{italicij}) = ({, \begin{matrix} 4 ε ([], {(\frac{σ}{r_{italicij}})}^{12} - {(\frac{σ}{r_{italicij}})}^{6} - {(\frac{σ}{r_{italiccij}})}^{12} + {(\frac{σ}{r_{italiccij}})}^{6}), & r_{ij} \leq r_{cij}, \\ 0, & r_{ij} > r_{cij}, \end{matrix})

where ε is the well‐depth and r cij is the cutoff radius. Different beads were connected with finitely extensible nonlinear elastic bonds (FENE).…”

Section: Modelmentioning

confidence: 99%

“…Different beads were connected with finitely extensible nonlinear elastic bonds (FENE). The FENE potential is expressed as 24,26

U_{Bond} ((), r_{italicij}) = ({, \begin{matrix} - 0.5 k R_{0}^{2} \ln ([], 1 - {(\frac{r_{italicij}}{R_{0}})}^{2}), & r_{ij} \leq R_{0}, \\ \infty, & r_{ij} > R_{0}, \end{matrix})

where r ij is the distance between beads i and j , k = 25 ε / σ 2 and R 0 is the maximum extension of the bond 27 ( R 0 = 1.5 σ ). The solvent molecules are implicitly considered.…”

Section: Modelmentioning

confidence: 99%

“…In addition to the electrostatic interactions, bead-bead interactions were considered in order to mimic the macroscopic solvent conditions. These interactions are calculated using a truncated Lennard-Jones potential 25,26 :…”

Section: Modelmentioning

confidence: 99%

“…Different beads were connected with finitely extensible nonlinear elastic bonds (FENE). The FENE potential is expressed as 24,26 U Bond r ij À Á = −0:…”

Section: Modelmentioning

confidence: 99%

“…The reduced temperature of the simulation T* was set to T* = k B T/ε = 2 corresponding to bad solvents conditions. 27 Different cut-off distances in the Lennard-Jones potential were used 25,26 to describe the interactions between copolymer units. The B-B and C-C interactions were considered attractive (r cij = 2.5σ).…”

Section: Modelmentioning

confidence: 99%

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Micellization through complexation of oppositely charged diblock copolymers: Effects of composition, polymer architecture, salt of different valency, and thermoresponsive block

Gioldasis

Gergidis

Vlahos

2020

Journal of Polymer Science

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The structural and electrical characteristics of polyelectrolyte complex micelles (PCMs) formed by mixing of oppositely charged double hydrophilic copolymers are studied by means of molecular dynamics simulations. In mixtures of linear diblock copolymers we found that the preferential aggregation numberNpof PCMs is a universal function of the ratioγ±of the total positive to total negative charges of the mixture. The addition of divalent salts ions induces a secondary micellization. In mixtures of copolymers bearing a common neutral thermoresponsive block, micelles with contracted corona consisting of thermoresponsive blocks and complex polyelectrolyte core are formed at low salt concentration and temperature far away the biphasic regime. At high salt concentration and temperature in the biphasic regime, reversed micelles are obtained. In equimolar mixtures of linear copolymers with miktoarm stars we found thatNpof PCMs decreases as the number of charged branches of miktoarm copolymer increases. The shape of micelles progressively changes from spherical to worm‐like with the increase of number of branches of miktoarm copolymers. Our findings are in full agreement with existing experimental and theoretical predictions and provides new and additional insights.

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U_{LJ} ((), r_{italicij}) = ({, \begin{matrix} 4 ε ([], {(\frac{σ}{r_{italicij}})}^{12} - {(\frac{σ}{r_{italicij}})}^{6} - {(\frac{σ}{r_{italiccij}})}^{12} + {(\frac{σ}{r_{italiccij}})}^{6}), & r_{ij} \leq r_{cij}, \\ 0, & r_{ij} > r_{cij}, \end{matrix})

where ε is the well‐depth and r cij is the cutoff radius. Different beads were connected with finitely extensible nonlinear elastic bonds (FENE).…”

Section: Modelmentioning

confidence: 99%

“…Different beads were connected with finitely extensible nonlinear elastic bonds (FENE). The FENE potential is expressed as 24,26

U_{Bond} ((), r_{italicij}) = ({, \begin{matrix} - 0.5 k R_{0}^{2} \ln ([], 1 - {(\frac{r_{italicij}}{R_{0}})}^{2}), & r_{ij} \leq R_{0}, \\ \infty, & r_{ij} > R_{0}, \end{matrix})

where r ij is the distance between beads i and j , k = 25 ε / σ 2 and R 0 is the maximum extension of the bond 27 ( R 0 = 1.5 σ ). The solvent molecules are implicitly considered.…”

Section: Modelmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

“…Different beads were connected with finitely extensible nonlinear elastic bonds (FENE). The FENE potential is expressed as 24,26 U Bond r ij À Á = −0:…”

Section: Modelmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

See 3 more Smart Citations

Micellization through complexation of oppositely charged diblock copolymers: Effects of composition, polymer architecture, salt of different valency, and thermoresponsive block

Gioldasis

Gergidis

Vlahos

2020

Journal of Polymer Science

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Complexation of a Polyelectrolyte Brush with Oppositely Charged AB Diblock Copolymers: The Zipper Brushes

Gioldasis

Gergidis

Vlahos

2022

Macro Theory & Simulations

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The internal stratification of a polyelectrolyte complex (zipper brush) formed by mixing of an anionic charged polyelectrolyte brush (PEB) with cationic-neutral diblock copolymers bearing a very long neutral block is studied by means of molecular dynamics simulations. The authors find that the fraction of the neutralized PEB units in the mixture increases as the fraction of the PEB charged units (a) increase for high grafting densities (d). Due to the charge neutralization condition, from the initial PEB through the complexation with the appropriate choice of a cationic-neutral copolymer, neutral brush having grafting density lower, equal, or much higher than that of the PEB are obtained. The addition of monovalent salt in the mixture with concentrations 0.1 and 1 m leads to a reduction in complexed diblock copolymer chains of up to 91% and practically the initial PEB is recovered. The findings are in full agreement with existing experimental predictions and provide new insights into the structure and the shape of the coacervate. The latter progressively changes from a dense film to perforated film, to lamella, to pinned micelles, to stacks as a, d, and the molecular weights of the PEB and diblock copolymer blocks are altered.

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Solution Properties of Polyelectrolytes with Divalent Counterions

et al. 2021

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Divalent ions are known to strongly influence the phase behavior, conformation, and flow properties of polyelectrolytes in solution. Here, we report small-angle neutron scattering and viscosity data for the magnesium salt of polystyrene sulfonate (MgPSS) in salt-free water and compare these results with analogous measurements for NaPSS. In a dilute solution, both salts are found to exhibit a rod-like conformation for high degrees of polymerization, but the chain dimensions of MgPSS are significantly smaller than for NaPSS, which is consistent with the lower charge density of MgPSS found from conductivity data. In the semidilute regime, the correlation length scales as ξ ≃ 3.7c −1/2 nm for NaPSS and ξ ≃ 5.4c −1/2 nm for MgPSS. At high concentrations, deviations to weaker power laws are observed for both salts. The variation of the viscosity with the degree of polymerization (η sp ∼ N) is consistent with unentangled, Rouse-like dynamics. Fuoss-law-type behavior (η sp ∼ c 1/2 ) is observed at low polymer concentrations, which turns into a stretched exponential dependence at high c, perhaps due to an increase in the local friction experienced by polymer segments.

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Mixed brushes consisting of oppositely charged Y‐shaped polymers in salt free, monovalent, and divalent salt solutions

Cited by 5 publications

References 39 publications

Micellization through complexation of oppositely charged diblock copolymers: Effects of composition, polymer architecture, salt of different valency, and thermoresponsive block

Micellization through complexation of oppositely charged diblock copolymers: Effects of composition, polymer architecture, salt of different valency, and thermoresponsive block

Complexation of a Polyelectrolyte Brush with Oppositely Charged AB Diblock Copolymers: The Zipper Brushes

Solution Properties of Polyelectrolytes with Divalent Counterions

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