Change of Elastic Modulus of Strongly Charged Hydrogels at the Collapse Transition

Zaroslov, Yuri D.; Philippova, Olga E.; Khokhlov, Alexei R.

doi:10.1021/ma980433a

Cited by 32 publications

(23 citation statements)

References 12 publications

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“…That is, the charge density dependence of the collapse region was most significant for alcohols and hardly observed for AcN systems. A similar result was found by Zaroslov et al21 for an anionic gel having sulfonate groups in aqueous EtOH; the transition region (EtOH concentration) slightly shifted to a lower concentration as the charge density increased from 80 to 100%. The authors ascribed the shift to an enhanced number of the bound counterions available for the aggregation of the charged groups with increasing charge density.…”

Section: Resultssupporting

confidence: 88%

Specific swelling behaviors of alkali‐metal poly(styrene sulfonate) gels in aqueous solvent mixtures

Fukunaga

Hayashi

Satoh

2007

J Polym Sci B Polym Phys

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Counterion-and solvent-specific swelling behaviors were investigated for alkali-metal poly(styrene sulfonate) (PSSM) gels having different degrees of sulfonation in aqueous organic solvent mixtures [water plus methanol, ethanol, 2-propyl alcohol, t-butyl alcohol, dimethyl sulfoxide (DMSO), acetone, acetonitrile, tetrahydrofuran, or dioxane]. With an increasing organic solvent concentration, most gel systems, except for DMSO, showed a volume phase transition. The transition abruptly occurred without significant deswelling in the lower solvent concentration region. Such swelling behavior contrasted with that of other common charged gel systems, including alkali-metal polyacrylate (PAAM) gels, which showed gel collapse after gradual deswelling with an increasing organic solvent concentration. The dielectric constant at the critical transition point (D cr ) for most mixed solvent systems decreased in the order of PSSK ! PSSCs ! PSSNa > PSSLi; that is, larger counterion systems were favorable for the transition. The counterion specificity also contrasted with our previous results for PAAM gels: PAANa > PAAK > PAALi $ PAACs. On the other hand, the solvent specificity for the PSSM gels was similar to that for the PAAM gels; the higher the dielectric constant was of the organic solvent, the higher the D cr value was at which the transition occurred. These specificities were examined on the basis of the solvation properties of the counterions and polymer charged groups and the solvent properties such as the Gutmann-Mayer donor number and acceptor number.

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Section: Resultssupporting

confidence: 88%

Specific swelling behaviors of alkali‐metal poly(styrene sulfonate) gels in aqueous solvent mixtures

Fukunaga

Hayashi

Satoh

2007

J Polym Sci B Polym Phys

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“…Figure 6 shows the experimental stress-deformation ratio curve of the as-prepared tetra-PEG gel (Q=1) and the theoretical curve predicted using Eq. (24). The stresses were normalized by their Young's moduli E. For comparison, the curve calculated with the neo-Hookean (NH) model , ( 2 5 ) is also shown 49 .…”

Section: Comparison With the Elasticity Modelsmentioning

confidence: 99%

“…Uniaxial normalized stress-deformation ratio curves of the as-prepared tetra-PEG gel determined via an experiment and calculated using the WLC model (Eqs. (19,21,24)). The curve calculated based on NH model (Eq.…”

Section: Comparison With the Elasticity Modelsmentioning

confidence: 99%

“…Such modulus upturn is caused by the non-linear strain hardening of the network strands owing to their finite extensibility, which is typically described with the inverse Langevin function or the worm-like chain model. To describe such non-linear elasticity of a gel in high-swelling regime, some swelling models considering finite extensibility of the network strands have been proposed 19,[21][22][23][24] . However, these models always require additional network parameters such as contour length of a network strand Rmax.…”

Section: Introductionmentioning

confidence: 99%

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Network elasticity of a model hydrogel as a function of swelling ratio: from shrinking to extreme swelling states

et al. 2018

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In this work, we intended to investigate the relationship between the swelling ratio Q and Young's modulus E of hydrogels from their contracted state to extreme swelling state and elucidate the underlining molecular mechanism. For this purpose, we used tetra-poly(ethylene glycol) (tetra-PEG) gel whose network parameters are well known as the polymer backbone, and succeeded in tuning the swelling of the gel by a factor of 1500 times while maintaining the topological structure of the network unchanged, using an approach combining molecular stent method and PEG dehydration method. A master curve of Q-E, independent of the method of obtaining Q, was obtained. Using the worm-like chain model, the experimentally determined master curve can be well reproduced. We also observed that the uniaxial stress-strain curve of the hydrogel can be well predicted by the worm-like chain model using the structure parameters determined from the fitting of Q-E experiment curve.

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“…[37][38][39] Takigawa et al 40 observed that the elastic modulus of PNIPA gels in a collapsed state was much higher than that in a swollen state because of the formation of physical crosslinks at a high PNIPA net-work concentration. Zaroslov et al 41 published a article concerning the swelling and mechanical behavior of polyelectrolyte gels in mixtures of good and poor solvents. In a good solvent region for weakly charged gels, the shear modulus decreased with the gel swelling.…”

Section: Introductionmentioning

confidence: 99%

Semi‐interpenetrating polymer networks composed of poly(N‐isopropyl acrylamide) and polyacrylamide hydrogels

Djonlagić

Petrovìć

2004

J Polym Sci B Polym Phys

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Three series of semi‐interpenetrating polymer networks, based on crosslinked poly(N‐isopropyl acrylamide) (PNIPA) and 1 wt % nonionic or ionic (cationic and anionic) linear polyacrylamide (PAAm), were synthesized to improve the mechanical properties of PNIPA gels. The effect of the incorporation of linear polymers into responsive networks on the temperature‐induced transition, swelling behavior, and mechanical properties was studied. Polymer networks with four different crosslinking densities were prepared with various molar ratios (25:1 to 100:1) of the monomer (N‐isopropyl acrylamide) to the crosslinker (methylenebisacrylamide). The hydrogels were characterized by the determination of the equilibrium degree of swelling at 25 °C, the compression modulus, and the effective crosslinking density, as well as the ultimate hydrogel properties, such as the tensile strength and elongation at break. The introduction of cationic and anionic linear hydrophilic PAAm into PNIPA networks increased the rate of swelling, whereas the presence of nonionic PAAm diminished it. Transition temperatures were significantly affected by both the crosslinking density and the presence of linear PAAm in the hydrogel networks. Although anionic PAAm had the greatest influence on increasing the transition temperature, the presence of nonionic PAAm caused the highest dimensional change. Semi‐interpenetrating polymer networks reinforced with cationic and nonionic PAAm exhibited higher tensile strengths and elongations at break than PNIPA hydrogels, whereas the presence of anionic PAAm caused a reduction in the mechanical properties. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3987–3999, 2004

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Change of Elastic Modulus of Strongly Charged Hydrogels at the Collapse Transition

Cited by 32 publications

References 12 publications

Specific swelling behaviors of alkali‐metal poly(styrene sulfonate) gels in aqueous solvent mixtures

Specific swelling behaviors of alkali‐metal poly(styrene sulfonate) gels in aqueous solvent mixtures

Network elasticity of a model hydrogel as a function of swelling ratio: from shrinking to extreme swelling states

Semi‐interpenetrating polymer networks composed of poly(N‐isopropyl acrylamide) and polyacrylamide hydrogels

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