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Samchenko, Yu. M.; Ulberg, Z. R.; Komarskii, S. A.; Kovzun, I. G.; Protsenko, I. T.

doi:10.1023/a:1022375109856

Cited by 8 publications

(6 citation statements)

References 1 publication

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“…Our decreasing cross-linking efficiency with increasing AAc fraction is consistent with other rheological studies of lightly cross-linked acrylamide- co -acrylic acid hydrogels, but the reason is not well understood. On one hand, with increasing AAc fraction is a higher linear charge density but also a higher degree of electrostatic screening.…”

Section: Results and Discussionsupporting

confidence: 86%

“…More importantly, their study shows that rheological mesh sizes are comparable to those from swelling and probe-diffusion measurements at similar crosslinker concentrations (∼0.03 mol L −1 ). Our decreasing cross-linking efficiency with increasing AAc fraction is consistent with other rheological studies of lightly cross-linked acrylamide-co-acrylic acid hydrogels, 47 but the reason is not well understood. On one hand, with increasing AAc fraction is a higher linear charge density but also a higher degree of electrostatic screening.…”

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confidence: 87%

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Electrokinetic Sonic Amplitude of Polyelectrolyte Solutions and Networks

2020

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As a first step toward understanding the electroacoustic response of polyelectrolyte hydrogel nanocomposites, we systematically vary the linear charge density of acrylic acid-co-acrylamide polymer networks (at a fixed total polymer concentration) to ascertain how the charge and mobility affect the electrokinetic sonic amplitude (ESA) spectra. A weakly charged polymer registers a negative ESA (real part), which we attribute to dynamics of the elastic network and its charge, whereas a highly charged polymer registers a positive ESA, attributed to sodium counterions. A mechanistic theoretical model is proposed that attributes the transition to the subtle manner in which the hydrodynamic friction of the network strands scale with their linear charge density. Further insights are gained from the electrical conductivity and dynamic shear moduli (in the linear viscoelastic regime). The electrical conductivity is dominated by the mobility of the sodium counterions and is diminished by network hindrance and counterion condensation, and the storage modulus decreases systematically with the linear charge density, suggesting a dominant role of interchain electrostatics, and possibly electro-steric influence on the polymerization and cross-linking.

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Section: Results and Discussionsupporting

confidence: 86%

supporting

confidence: 87%

Electrokinetic Sonic Amplitude of Polyelectrolyte Solutions and Networks

2020

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“…Recently, spatially cross-linked p(AM-co-AA) hydrogels with superior antiburn properties have been synthesized, and their swelling, network parameters, and rheological properties have been evaluated. 10,11 Photolysis of the TiO 2 semiconductor results in the generation of valence band holes and conduction band electrons, which produce hydroxyl (OH • ) and superoxide radicals (O 2 -• ), which oxidize the organic matter present in water. Recently, we have developed combustion-synthesized nano anatase titania (CS TiO 2 ), 12,13 which has high specific surface area, high surface hydroxyl content, and low band gap compared to commercially available Degussa P25 TiO 2 (DP 25).…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Degradation of Poly(Acrylamide-co-acrylic Acid)

Vinu

Madras

2008

J. Phys. Chem. B

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Poly(acrylamide-co-acrylic acid) copolymers of different compositions were synthesized and characterized. The copolymers were statistical with a relatively high percentage of acrylamide units, as determined by (13)C NMR. Reactivity ratios calculated by the Finemann-Ross and Kelen-Tudos methods showed that the copolymers were random with a reactivity ratio of r AM = 3.76 and r AA = 0.28. The photolytic and photocatalytic degradation of the copolymers and the homopolymers was conducted in the presence of combustion-synthesized nano anatase titania. The degradation of the copolymer in the presence of combustion-synthesized titania was significantly higher than that observed in the presence of commercial titania, Degussa P-25. The degradation was modeled by using continuous distribution kinetics by following the time evolution of molecular weight distribution. The degradation follows a two step mechanism, wherein the rapid first step comprises the scission of weak acrylic acid units along the chain which is followed by the breakage of relatively strong acrylamide units. The rate constants for the weak and strong links follow a linear trend with the percentage of acrylic acid and acrylamide in the copolymer, respectively. This linear variation can be correlated with a similar trend observed for the activation energies obtained for the pyrolytic degradation of the polymers.

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“…Since, the pioneering work of Wichterle and Lim in 1960 on crosslinked poly(HEMA) [1], hydrogels have been of great interest to biomaterial scientists [1][2][3][4][5][6][7][8][9][10][11][12], mainly due to their hydrophilic character and potential biological compatibility. Hydrogels are polymeric networks, which absorb and retain large amounts of water.…”

Section: Introductionmentioning

confidence: 99%