Complexation Phenomena in pH-Responsive Copolymer Networks with Pendent Saccharides

Kim, Bumsang; Peppas, Nicholas A.

doi:10.1021/ma021201l

Cited by 41 publications

(11 citation statements)

References 34 publications

(58 reference statements)

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“…Thus, the swelling ratio at pH = 12 was lower than that at pH = 7. A similar trend was observed by Kim and Peppas (2002) [25] who studied the effects of pH on mesh size with varying PAA content. Before the gellation (pH=4), Carbopol 981 which has the lowest crosslink density exhibits the highest viscosity among the three samples ( Figure 7).…”

Section: Discussionsupporting

confidence: 82%

Use of a novel pH-triggered polymer-gel system for optimal mobility-control applications

et al. 2012

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There are two challenges in using polymers for conformance control applications in the petroleum industry. The first difficulty is to maintain a good injectivity to overcome the large pressure drop caused by the high viscosity of the polymers. Secondly, large polymer volumes required to be injected to compensate for polymer retention in a reservoir. The main objective of this work is to study the viability of using a pH-sensitive polyelectrolyte to alleviate the above two challenges. The results showed that the pH of the swelling medium has great effect on the swelling behavior of poly(acrylic acid) hydrogels. At low pH regime, the viscosity increases gradually as pH increases until certain pH value, 'critical pH' is reached. In the second regime and once critical pH value is exceeded, the viscosity increases sharply with the pH. This is followed by independency of the viscosity on pH, in the third regime. It was found that this sensitivity to the pH varies with the change in crosslink density and shear rates. At pH=4 (before the gellation), the sample (Carbopol 981) which has the lowest crosslink density exhibits the highest viscosity among the three samples. After the gellation (PH=8), the rheological behavior is reversed for the highest crosslinked density polymer (EZ-4) and the lowest crosslinked density polymer (981) which contradicts with the well known swelling ratio-crosslink density relation. It is concluded that the examined polymers are good candidates for mobility control applications. They can also be used for temporary zonal isolation since they can be easily broken down with mild acid wash and flowback.

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Section: Discussionsupporting

confidence: 82%

Use of a novel pH-triggered polymer-gel system for optimal mobility-control applications

et al. 2012

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“…In previous studies,28, 29 we observed that P(MAA‐ co ‐MEG) networks exhibited pH‐responsive swelling behavior and that the carboxylic acid groups of MAA became ionized at higher pH values than p K a of the polymer (pH ∼ 5).…”

Section: Resultsmentioning

confidence: 75%

Dynamic swelling behavior of pH‐sensitive anionic hydrogels used for protein delivery

Kim

Flamme

Peppas

2003

J of Applied Polymer Sci

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256

135

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There have been many attempts to use anionic hydrogels as oral protein delivery carriers because of their pH-responsive swelling behavior. The dynamic swelling behavior of poly(methacrylic acid-co-methacryloxyethyl glucoside) and poly(methacrylic acid-g-ethylene glycol) hydrogels was investigated to determine the mechanism of water transport through these anionic hydrogels. The exponential relation M t /M ϱ ϭ kt n (where M t is the mass of water absorbed at time t and M ϱ is the mass of water absorbed at equilibrium) was used to calculate the exponent (n) describing the Fickian or non-Fickian behavior of swelling polymer networks. The mechanism of water transport through these gels was significantly affected by the pH of the swelling medium. The mechanism of water transport became more relaxation-controlled in a swelling medium of pH 7.0, which was higher than pK a of the gels. The experimental results of the time-dependent swelling behaviors of the gels were analyzed with several mathematical models.

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“…At pH 1.2, the dominant charges in the beads are protonated carboxylic acid groups, which form hydrogen bonds in the networks and render the networks more hydrophobic. In the case of higher pH (6.8 and 7.4), the dominant charges in the gels are the un-protonated carboxylate groups, resulting in higher electrostatic repulsion in network and water would be taken up (Kim and Peppas, 2002;Zakhireh et al, 2014).…”

Section: Swelling Studymentioning

confidence: 99%

Carboxymethyl cellulose capsulated layered double hydroxides/drug nanohybrids for Cephalexin oral delivery

Barkhordari

Yadollahi

2016

Applied Clay Science

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Complexation Phenomena in pH-Responsive Copolymer Networks with Pendent Saccharides

Cited by 41 publications

References 34 publications

Use of a novel pH-triggered polymer-gel system for optimal mobility-control applications

Use of a novel pH-triggered polymer-gel system for optimal mobility-control applications

Dynamic swelling behavior of pH‐sensitive anionic hydrogels used for protein delivery

Carboxymethyl cellulose capsulated layered double hydroxides/drug nanohybrids for Cephalexin oral delivery

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