Phase Transition of Acrylamide‐Based Polyampholyte Gels in Water

Ceylan, Deniz; Can, Volkan; Okay, Oğuz

doi:10.1080/10601320600897056

Cited by 6 publications

(2 citation statements)

References 25 publications

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“…A number of polymer networks undergo a first order phasetransition when subjected to a small change in an external environmental parameter (e.g. temperature (Baysal & Karasz, 2003), pH (Ceylan, Can, & Okay, 2006) and solvent composition (Ilavsky et al, 1995)), at which an abrupt change in the volume is observed. Ilavsky and co-workers described polymeric networks in which a small variation in the composition of water/ethanol mixtures induces a jumpwise change in the volume of the gel, which is reflected in a simultaneous jumpwise change in the shear modulus (Ilavsky et al, 1995).…”

Section: Swelling Of Chitosan Membranes In Water/ethanol Mixturesmentioning

confidence: 99%

Effect of solvent-dependent viscoelastic properties of chitosan membranes on the permeation of 2-phenylethanol

Caridade

Silva

Reis

et al. 2009

Carbohydrate Polymers

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a b s t r a c tThe viscoelastic behaviour of chitosan was followed by dynamic mechanical analysis (DMA) while the sample was immersed in gradient compositions of water/ethanol mixtures. The swelling equilibrium of chitosan membranes, both crosslinked with genipin or not, increased linearly with the water content. Increasing the water content, it was simultaneously observed a peak in the loss factor (around 25 vol.%) and a reduction of the storage modulus, which was attributed to the a-relaxation of chitosan. This was the first time that the glass transition dynamics in a polymer was monitored in immersion conditions where the composition of the plasticizer in the bath is changed in a controlled way. The water content at which tan d presented a maximum increased with both increasing frequency and increasing crosslinking density. The permeability decreased steadily with the ethanol content, reaching very low values around the glass transition. Therefore we hypothesize that conformational mobility of the polymeric chains may play an important role in the diffusion properties of molecules trough polymeric matrices.

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Section: Swelling Of Chitosan Membranes In Water/ethanol Mixturesmentioning

confidence: 99%

Effect of solvent-dependent viscoelastic properties of chitosan membranes on the permeation of 2-phenylethanol

Caridade

Silva

Reis

et al. 2009

Carbohydrate Polymers

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“…Theoretical calculations show that this unique feature is due to the fact that the pH inside the gel differs from that of the external solution in the collapse region. Recently, we have investigated the behavior of AAm/MAPTAC/AAc hydrogels containing 70 mol % AAm and 30 mol % ionic comonomer with various proportions of MAPTAC and AAc units 17. It was shown that the collapsed plateau around the IEP becomes shorter as the MAPTAC content of the hydrogels decreases and, at 1 mol % MAPTAC, it becomes a point at the IEP, as usually observed in polyampholyte solutions.…”

Section: Introductionmentioning

confidence: 85%

Collapse of acrylamide‐based polyampholyte hydrogels in water

Dogu

Kilic

Okay

2009

J of Applied Polymer Sci

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The swelling behavior of balanced acrylamide (AAm)-based polyampholyte hydrogels in water and in aqueous salt (NaCl) solutions was investigated. Equimolar ratio of the ionic comonomers 4-vinylpyridine (cationic monomer) and acrylic acid (anionic monomer) were used together with the nonionic monomer AAm in the hydrogel preparation. The variations of the hydrogel volume in response to changes in pH were measured. It was found that the hydrogels are in a collapsed state not only at the pH of the isoelectric point pH IEP but also over a wide range of pH including pH IEP . The width of the collapsed plateau increased and the hydrogels assumed a more compact state as the ionic group content is increased. The antipolyelectrolyte behavior was observed along the collapsed plateau region, where the gel occupies a larger volume in salt solution. The experimental swelling data were compared with the predictions of the Flory-Rehner theory of swelling equilibrium including the ideal Donnan equilibria.

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An experimental investigation on transpiration cooling performances using solid hydrogel as coolant

Kang

Wang

et al. 2019

Applied Thermal Engineering

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Phase Transition of Acrylamide‐Based Polyampholyte Gels in Water

Cited by 6 publications

References 25 publications

Effect of solvent-dependent viscoelastic properties of chitosan membranes on the permeation of 2-phenylethanol

Effect of solvent-dependent viscoelastic properties of chitosan membranes on the permeation of 2-phenylethanol

Collapse of acrylamide‐based polyampholyte hydrogels in water

An experimental investigation on transpiration cooling performances using solid hydrogel as coolant

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