Deformational, swelling, and potentiometric behavior of ionized poly(methacrylic acid) gels. II. Experimental results

Hasa, J.; Ilavský, M.

doi:10.1002/pol.1975.180130204

Cited by 64 publications

(52 citation statements)

References 12 publications

(1 reference statement)

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“…The key point here is that pH, i, swelling ratio Q, and possibly G all differ in value between the initial and final states in this hypothetical experiment. This was also the case in previous studies of the hydrogel modulus at a pH-induced transition [9][10][11][12]. However, ambiguity arises in the interpretation of the results, because both Q and i might be expected to affect G. As an alternative, one can imagine lowering pH and simultaneously lowering the chemical potential of water in the environment below μ ref (i.e.…”

Section: Introductionmentioning

confidence: 80%

Separation of the effects of pH and polymer concentration on the swelling pressure and elastic modulus of a pH-responsive hydrogel

Horkay

Han

et al. 2006

Polymer

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The elastic shear modulus G and swelling pressure ω are studied for a basic, pH-responsive hydrogel synthesized by crosslinking copolymerization of co-monomers hydroxypropyl methacrylate and N,N-dimethylaminoethyl methacrylate with crosslinker tetraethylene glycol dimethacrylate. Under normal conditions of use as a "smart" material, hydrogel swelling ratio Q and pH vary simultaneously, but here G and ω values are presented as a function of pH with Q held constant and vice-versa. At fixed pH, G decreases with increase in Q in a power law dependence, as predicted by the FloryRehner model. However, at fixed Q, G increases with decrease in pH (i.e, increase in degree of ionization). The pH effect is more pronounced than the volume effect, thus the hydrogel stiffens as it swells in response to pH change. At high pH, ω values of the uncharged hydrogel obey the FloryRehner model, whereas explicit ionic contributions can be identified at lower pH values.

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Section: Introductionmentioning

confidence: 80%

Separation of the effects of pH and polymer concentration on the swelling pressure and elastic modulus of a pH-responsive hydrogel

Horkay

Han

et al. 2006

Polymer

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“…Most of these studies have been concentrated on hydrogels containing weakly ionizable groups such as the carboxylate groups. [1][2][3][4][5][6][7] The swelling properties of these weak polyelectrolyte gels strongly vary depending on the pH of the solution.…”

Section: Introductionmentioning

confidence: 99%

Swelling behavior of anionic acrylamide-based hydrogels in aqueous salt solutions: Comparison of experiment with theory

Okay

Sariişik

Zor

1998

J. Appl. Polym. Sci.

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A series of hydrogels were prepared from acrylamide and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) monomers with 0 -80 mol % AMPS and using N,NЈ-methylenebis(acrylamide) as the crosslinker. The swelling capacities of hydrogels were measured in water and in aqueous NaCl solutions. The volume swelling ratio q v of hydrogels in water increases sharply when the mole fraction f c of AMPS increases from 0 to 0.06. At higher values of f c from 0.06 up to 0.18, no change in the swelling capacities of hydrogels was observed; in this range of f c , q v becomes nearly constant at 750. However, as f c further increases, q v starts to increase again monotonically over the entire range of f c . At a fixed value of f c , the swelling ratio of hydrogels decreases with increasing salt concentration in the external solution. The results of the swelling measurements in aqueous salt solutions were compared with the predictions of the Flory-Rehner theory of swelling equilibrium. It was shown that the theory correctly predicts the swelling behavior of hydrogels up to 80 mol % charge densities. The method of estimation of the network parameters was found to be unimportant in the prediction of the experimental swelling data. The network parameters used in the simulation only correct the deficiency of the swelling theory.

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“…A t an MA content 130 mole-%, the dependence of G, on cy passes through a minimum; similar results were obtained earlier for gels of pure PMA. 6 The volume fraction of the polymer in the swollen gel, u2, decreases within the whole neutralization region; the decrease becomes larger with increasing MA content in the copolymer (Table 11). …”

Section: Dependence Of Deformational Behavior On Neutralizationmentioning

confidence: 97%

“…The time interval of 2 min was sufficiently short so that no change in swelling with deformation for samples with higher a values was observed. 6 After the measurement had been completed, pH, value was measured again; the difference between the two values was lower than 0.1 in all cases. With …”

Section: Measurement Of Deformational Characteristicsmentioning

confidence: 99%

Deformational, swelling, and potentiometric behavior of ionized gels of 2‐hydroxyethyl methacrylate–methacrylic acid copolymers

Ilavský

Dušek

Vacı́k

et al. 1979

J of Applied Polymer Sci

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SynopsisThe deformational, swelling, and potentiometric behavior of ionized water-swollen gels of 2-hydroxyethyl methacrylate (HEMA)-methacrylic acid (MA) c,opolymers used in biomedical and separation applications was investigated. With increasing degrees of neutralization a, the swelling degree strongly increases and the modulus G, decreases. For the copolymers with MA content 1 30 mole-%, the dependence of G, on a passes through a minimum. Comparison of the results with the modified theory of rubber elasticity shows that the decrease in G, at low concentrations of charges on the chain is controlled mainly by the degree of swelling. At higher a, both the finite extensibility of network chains, caused by a high degree of swelling, and electrostatic interactions contribute to G,. The dependence of the interaction parameter x on the volume fraction of polymer in the gel, uz, is independent of a and closely resembles the dependence obtained for other hydrophilic polymers.

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Deformational, swelling, and potentiometric behavior of ionized poly(methacrylic acid) gels. II. Experimental results

Cited by 64 publications

References 12 publications

Separation of the effects of pH and polymer concentration on the swelling pressure and elastic modulus of a pH-responsive hydrogel

Separation of the effects of pH and polymer concentration on the swelling pressure and elastic modulus of a pH-responsive hydrogel

Swelling behavior of anionic acrylamide-based hydrogels in aqueous salt solutions: Comparison of experiment with theory

Deformational, swelling, and potentiometric behavior of ionized gels of 2‐hydroxyethyl methacrylate–methacrylic acid copolymers

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