Swelling and collapse of polymer gel in polymer solutions and melts

Vasilevskaya, V. V.; Khokhlov, A. S.

doi:10.1021/ma00027a059

Cited by 49 publications

(27 citation statements)

References 7 publications

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“…As expected, [12,16,24] the PEG concentration inside the gel is always smaller than that in the solution, i. e., m 3 /b a Figure 1. Variation of the swelling ratio V/V w of PNIPA gels (filled symbols) and PAAm gels (open symbols) with the concentration of PEG-300 in the outer solution.…”

Section: Resultssupporting

confidence: 69%

“…[1 -11] Recently, we have reported swelling behavior of both weak-and strong-polyelectrolyte poly(acrylamide) (PAAm) hydrogels in aqueous solutions of poly(ethylene glycol)s (PEG) as well as PAAm's of various molecular weights. [12 -15] As predicted theoretically, [16] we observed a first-order volume phase transition in ionic PAAm hydrogels immersed in PEG solutions, if both the chain length and the concentration of PEG in the external solution assume critical values. [12,15] These experimental findings can be explained semi-quantitatively within the framework of the classical Flory-Huggins (FH) theory.…”

Section: Introductionsupporting

confidence: 70%

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Reentrant Phase Transition of Strong Polyelectrolyte Poly(N-isopropylacrylamide) Gels in PEG Solutions

Melekaslan

Okay²

2001

Macromol. Chem. Phys.

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Section: Resultssupporting

confidence: 69%

Section: Introductionsupporting

confidence: 70%

Reentrant Phase Transition of Strong Polyelectrolyte Poly(N-isopropylacrylamide) Gels in PEG Solutions

Melekaslan

Okay²

2001

Macromol. Chem. Phys.

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“…Indeed, although the predictions of this theory have been experimentally verified using a few model synthetic hydrogels (30,31), its applicability to the more complex case of biological hydrogels such as colonic mucus is unclear. One signature of this form of compression is its tunability: More concentrated polymer solutions should induce more hydrogel compression (29,30). Consistent with this prediction, we found that mucus compression was tunable by PEG concentration (green points in Fig.…”

Section: Significancesupporting

confidence: 83%

“…Large nonpenetrating polymers have been used to osmotically compress synthetic hydrogels (26) and even the periciliary brush after mucus removal in the mammalian lung (27). However, the possibility that even polymers small enough to penetrate a hydrogel could compress it was first recognized by Brochard in 1981 (28) and was subsequently investigated both theoretically and experimentally (29,30) (further references are provided in SI Materials and Methods). In this case, hydrogel compression arises from a combination of enthalpic and entropic effects.…”

Section: Significancementioning

confidence: 99%

“…Another effect arises from the free energy penalty associated with penetrating the hydrogel mesh: This can lead to an elevated polymer concentration, and therefore an elevated osmotic pressure, outside the hydrogel, which similarly forces the hydrogel to compress. Clarifying the role of these, and other, different effects remains unresolved, even for the case of synthetic hydrogels; however, such effects can be described collectively using the classic Flory-Huggins theory of polymer solutions (29,30). We therefore asked whether this physical framework could also describe polymer-induced compression of the colonic mucus hydrogel.…”

Section: Significancementioning

confidence: 99%

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Polymers in the gut compress the colonic mucus hydrogel

Datta

Steinberg

Ismagilov

2016

Proc. Natl. Acad. Sci. U.S.A.

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Colonic mucus is a key biological hydrogel that protects the gut from infection and physical damage and mediates host-microbe interactions and drug delivery. However, little is known about how its structure is influenced by materials it comes into contact with regularly. For example, the gut abounds in polymers such as dietary fibers or administered therapeutics, yet whether such polymers interact with the mucus hydrogel, and if so, how, remains unclear. Although several biological processes have been identified as potential regulators of mucus structure, the polymeric composition of the gut environment has been ignored. Here, we demonstrate that gut polymers do in fact regulate mucus hydrogel structure, and that polymer-mucus interactions can be described using a thermodynamic model based on Flory-Huggins solution theory. We found that both dietary and therapeutic polymers dramatically compressed murine colonic mucus ex vivo and in vivo. This behavior depended strongly on both polymer concentration and molecular weight, in agreement with the predictions of our thermodynamic model. Moreover, exposure to polymer-rich luminal fluid from germ-free mice strongly compressed the mucus hydrogel, whereas exposure to luminal fluid from specific-pathogen-free mice-whose microbiota degrade gut polymers-did not; this suggests that gut microbes modulate mucus structure by degrading polymers. These findings highlight the role of mucus as a responsive biomaterial, and reveal a mechanism of mucus restructuring that must be integrated into the design and interpretation of studies involving therapeutic polymers, dietary fibers, and fiber-degrading gut microbes.hydrogel | biophysics | biomaterials | polymers | mucus B iological hydrogels (including mucus, blood clots, and the extracellular matrix) provide critical functions, yet little is known about how their structure is influenced by materials they come into contact with regularly. For example, the environments of many hydrogels abound in polymers, such as dietary fibers (1, 2) or administered therapeutics (3-5) in the gut and soluble glycoproteins in tissues. Whether such polymers interact with these hydrogels, and if so, how, remains unclear. An important example is the case of colonic mucus, which protects the gut from infection and physical damage (6-8), mediates drug delivery (9), and mediates host-microbe interactions (10) in a structure-dependent manner; for example, a "tighter" mesh could impede the infiltration of microorganisms from the intestinal lumen (6, 11-13). Mucus restructuring is typically attributed solely to changes in secretion (14-16), or to the activity of specific enzymes (8, 17), detergents (18), or dextran sulfate sodium-induced inflammation (19). However, the physicochemical properties of the gut environment itself-particularly its polymeric composition-have not been considered as a potential regulator of mucus structure. We therefore sought to characterize the structure of the colonic mucus hydrogel in the absence and in the presence of polymers. Res...

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Volume Phase Transition of Polymer Networks in Polymeric Solvents

Okay

Gundogan

2002

Macromol. Theory Simul.

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A strong concentration dependence of the solvent–polymer interaction parameter χ is known to be a requirement for the first‐order volume phase transition in uncharged polymer networks in solvents. Another possibility for the observation of phase transition in nonpolar networks is to increase the number of lattice sizes occupied by a solvent molecule. This possibility has been indicated earlier and is worked out in detail in this paper. Using the theory of swelling equilibrium, we examine the polymer network systems immersed in a polymer melt. The critical conditions for the phase transition in both uncharged and ionic networks are described.

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Swelling and collapse of polymer gel in polymer solutions and melts

Cited by 49 publications

References 7 publications

Reentrant Phase Transition of Strong Polyelectrolyte Poly(N-isopropylacrylamide) Gels in PEG Solutions

Reentrant Phase Transition of Strong Polyelectrolyte Poly(N-isopropylacrylamide) Gels in PEG Solutions

Polymers in the gut compress the colonic mucus hydrogel

Volume Phase Transition of Polymer Networks in Polymeric Solvents

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