Rheological Scaling of Ionic Liquid-Based Polyelectrolytes in the Semidilute Unentangled Regime from Low to High Salt Concentrations

Matsumoto, Atsushi; Yoshizawa, Ryota; Urakawa, Osamu; Inoue, Tadashi; Shen, Amy Q.

doi:10.1021/acs.macromol.1c00576

Cited by 16 publications

(31 citation statements)

References 103 publications

(204 reference statements)

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“…This equation is in moderate agreement with experimental evidence reported for several systems; see refs and for a review of the N and c dependences of flexible polyelectrolytes with monovalent counterions. For NaPSS in DI water, the viscosity–concentration power-law exponent for untangled solutions does not take a constant value and instead increases with polymer concentration, a fact which has also been observed for other systems . A qualitatively similar trend is observed here for MgPSS.…”

Section: Resultssupporting

confidence: 85%

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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Section: Resultssupporting

confidence: 85%

Solution Properties of Polyelectrolytes with Divalent Counterions

et al. 2021

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“…In salt-free or low ionic strength media, polyelectrolytes adopt highly extended conformations, ,− which indicates that their solutions are above the overlap concentration ( c *) for most practical applications. While the overlap concentration of polyelectrolytes is much lower than that of nonionic polymers, especially for high degrees of polymerization ( N ), the entanglement concentration ( c e ) is only weakly dependent on the charge fraction. ,, As a result, there exists a wide range in the N – c phase-space, where polyelectrolytes are in the semidilute unentangled regime ( c * < c < c e ). ,, For example, sodium polystyrene sulfonate (NaPSS) with N ≃ 2000 displays c e / c * ≃ 10 3 in salt-free water.…”

Section: Introductionmentioning

confidence: 99%

Diffusion and Viscosity of Unentangled Polyelectrolytes

et al. 2021

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We report chain self-diffusion and viscosity data for sodium polystyrene sulfonate (NaPSS) in semidilute salt-free aqueous solutions measured by pulsed-field gradient NMR and rotational rheometry, respectively. The molecular weight of NaPSS is characterized using five techniques. Relationships between M w and the intrinsic viscosity and diffusion coefficient in excess salt are established. These are helpful for the accurate determination of the molar mass of NaPSS. The observed concentration dependence of η and D are consistent with the Rouse–Zimm scaling model if the monomeric friction coefficient (ζ) is concentration-dependent. The concentration dependence of ζ exceeds that expected from free-volume models of diffusion, and its origin remains unclear, possibly being related to electrostatic effects. Correlation blobs and dilute chains with equivalent end-to-end distances exhibit nearly equal friction coefficients, in agreement with scaling. Viscosity and diffusion data are combined using the Rouse model to calculate the single-chain dimensions of NaPSS in salt-free solution, and the results overpredict direct SANS measurements of the radii of gyration by a factor of ≃1.4.

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“…The observed increase in the screening length at high IL concentrations is unexpected, and named as the charge underscreening effect to specify such a unique screening behavior. 83) Motivated by the above observation, Matsumoto et al 68,69) conducted systematic rheological characterizations of a PIL, poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide) (PC 4 -TFSI), in a mixture of an IL, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Bmim-TFSI), and a non-ionic solvent, dimethylformamide (DMF). Specifically, they evaluated the specific viscosity η sp and the longest relaxation time λ while varying IL concentrations c IL at a fixed monomer concentration c p in both dilute and semidilute unentangled regimes.…”

Section: Polymerized Ionic Liquids In Ionic Liquid Solutionsmentioning

confidence: 99%

“…Specifically, they evaluated the specific viscosity η sp and the longest relaxation time λ while varying IL concentrations c IL at a fixed monomer concentration c p in both dilute and semidilute unentangled regimes. In order to explain the observed non-monotonic dependence of η sp on c IL , Matsumoto et al 69) proposed a new charge screening model, given by…”

Section: Polymerized Ionic Liquids In Ionic Liquid Solutionsmentioning

confidence: 99%

“…63) It should be also emphasized that polymerized ionic liquids, consisting of bulky cations and anions weakly coordinated, have been attracting research interests as a new class of polyelectrolytes in the past two decades. 64) Since polymerized ionic liquids can dissolve into organic solvents with low dielectric constants (e.g., THF and methanol) [65][66][67] as well as ion concentrated solutions (e.g., ionic liquids), 68,69) how electrostatic interactions act on polyelectrolyte chains in such solvents is another interesting subject matter to be addressed.…”

Section: Introductionmentioning

confidence: 99%

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Rheology of Polyelectrolyte Solutions: Current Understanding and Perspectives

Matsumoto

2022

J. Soc. Rheol., Jpn

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Polyelectrolytes with ionic groups are abundant in nature and essential in life. Counterions can be released into a solution and leave charges on polyelectrolyte chains, making the solution properties significantly different from those of electrically neutral polymers. A lot of scientific efforts have been made to elucidate the effect of electrostatic interactions on the conformation and material properties of polyelectrolyte solutions. However, unfortunately, our understanding is still far away from being perfect, and continuous efforts need to be provided by researchers from different aspects. This short review will highlight the research progress made in the past few years on the conformation and viscoelastic properties of polyelectrolyte solutions.

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Rheological Scaling of Ionic Liquid-Based Polyelectrolytes in the Semidilute Unentangled Regime from Low to High Salt Concentrations

Cited by 16 publications

References 103 publications

Solution Properties of Polyelectrolytes with Divalent Counterions

Solution Properties of Polyelectrolytes with Divalent Counterions

Diffusion and Viscosity of Unentangled Polyelectrolytes

Rheology of Polyelectrolyte Solutions: Current Understanding and Perspectives

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