Physical gels from PVC: dynamic properties of dilute solutions

Candau, S. J.; Dormoy, Y.; Mutin, P. Hubert; Debeauvais, F.; Guenet, Jean‐Michel

doi:10.1016/0032-3861(87)90448-4

Cited by 21 publications

(20 citation statements)

References 13 publications

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“…The protein concentration is not sufficient at these low concentrations for a 3D network that stretches across the full volume of the sample to form resulting in slow flowing, weak gels or viscous solutions. The presence of small gel-like aggregates below the critical gelation concentration was first shown for PVC physical gels using light scattering by Mutin et al 39,40…”

Section: Thermal Behaviour and Molecular Transitionsmentioning

confidence: 93%

Thermoreversible lysozyme hydrogels: properties and an insight into the gelation pathway

et al. 2008

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The gelation behaviour of aqueous solutions of hen egg white lysozyme (HEWL) in the presence of 20 mM DTT in the concentration range 0.7 to 4.0 mM has been investigated using microDSC, FTIR, cryoTEM, SANS and oscillatory rheology. The macroscopic critical gelation concentration, C gel , was found to be $ 3.0 mM. The disruption of the disulfide bonds by the DTT and the destabilisation of the protein were found to be a prerequisite for the formation of b-sheet rich fibrils under the mild conditions used in this work. Using our methodology the hydrogels obtained have a pH of 7, hence are suitable for cell culture, and are also thermoreversible. The hydrogel melting temperature was found to increase with increasing concentration and a similar structure was observed across the concentration range investigated. Our results suggest these systems are composed of a well defined regular network where single b-sheet rich fibrils ($ 3 nm diameter) form initially, then two of these fibrils associate two-by-two to form junctions ($ 6 nm diameter) and then on cooling further aggregate to form larger bundles of fibres. The network mesh size was found to decrease with increasing concentration. Our results suggest that below C gel small unconnected gel-like aggregates exist that have a similar structure to the hydrogels obtained above C gel . Using our data we propose a model for the denaturation and gelation behaviour of our system. During the first heating an a-helix to b-sheet molecular transition for the protein conformation occurs resulting in b-sheet rich fibrils forming through the self-assembly of b-sheet rich denaturated proteins. At high temperature the solution contains b-sheet rich fibrils with dissolved protein. On cooling an increase in the amount of b-sheet was observed via FTIR suggesting that as the temperature is decreased more and more protein forms b-sheet rich fibrils. At the gelation temperature these fibrils associate two-by-two to form the network junctions resulting in the macroscopic gelation of the sample. Our results suggest the network junctions are formed via specific hydrophobic interactions. The hydrogels elastic modulus was found to scale as C 2.45 for C > C gel .

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Section: Thermal Behaviour and Molecular Transitionsmentioning

confidence: 93%

Thermoreversible lysozyme hydrogels: properties and an insight into the gelation pathway

et al. 2008

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“…Two polar solvents used in this study have similar molar volumes V and solubility parameters o, CIBz (u=107 cm 3 mol-1 ; o= 9.5 cal 0 • 5 cm-1. 5 ) and NrBz (v= 103 cm 3 mol-1 ; o= 10 cal 0 • 5 cm-1. 5 ), and PVC has the solubility parameter o= 9.6 cal 0 • 5 cm -1.5.…”

Section: Analysis Of Nmr Decaying Signalsmentioning

confidence: 99%

“…5 ) and NrBz (v= 103 cm 3 mol-1 ; o= 10 cal 0 • 5 cm-1. 5 ), and PVC has the solubility parameter o= 9.6 cal 0 • 5 cm -1.5. Obviously, these solubility parameters cannot be used to clarify the interaction between PVC and solvent.…”

Section: Analysis Of Nmr Decaying Signalsmentioning

confidence: 99%

Solvent Effect on Structural Formation and Molecular Mobility of Polyvinyl Chloride Gels

Hong

Huang

2000

Polym J

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In this work, the interaction between polyvinyl chloride (PVC) and organic solvents was first investigated through viscometric results and the donor-acceptor electron properties. The results clearly showed that the affinity ofnitrobenzene (NrBz) to PVC is higher than that of chlorobenzene (C!Bz). On the other hand, the critical gel concentrations Cgei' are 1.7 gdL-1 and 6 gdL 1, respectively, for the PVC/C!Bz and PVC/NrBz solutions at 30°C, indicating that the polymer-solvent interaction directly affects the gelation ability. Then, the structural formation and the molecular mobility of PVC gels were investigated using pulsed 1 H NMR analyses. The CPMG decaying signals from pulsed NMR measurement of the PVC gels could be decomposed into three components, reflecting respectively the proton mobility in the junction zone, in the polymer-rich phase and in the solvent-rich phase of the gel network. The solutions began to appear the fraction of junction zones at PVC concentration above 1.5 g dL-1 and 6 g dL-1, respectively, in the PVC/C!Bz and PVC/NrBz solutions, while the formation of the junction zones could interconnect the polymer chains into a three-dimensional network structure macro-domain. As the immobile junction zones were formed, the mobility of the PVC chains was reduced and the mobility of the solvent molecules could also be suppressed. This phenomenon typically appeared in the polymer/poor solvent (PVC/CIBz) system. Through the observation of the diffusion property of the solvent molecules, we can clearly show that the gel network in PVC/C!Bz gels is denser than that of PVC/NrBz gels.

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“…As for most physical gels, the detailed junction structure of PVC gels is not completely understood. It has been proposed that PVC gels have a fringed-micelle structure, in which PVC crystallites knot together the solvated chains and develop a 3-D network, as has been shown with small and wide angle X-ray scattering, [3][4][5][6] light scattering, [7][8][9] and small angle neutron scattering (SANS), 1 differential scanning calorimetry (DSC), 10 spectroscopy, 11,12 and microscopy. 2,10,13 Another model has been proposed in which the network structure consists of an array of fibrous crystals.…”

Section: Introductionmentioning

confidence: 99%

“…2,10,13 Another model has been proposed in which the network structure consists of an array of fibrous crystals. [3][4][5][6] First, based on a SANS study of PVC gels formed in diethyl oxalate and bromobenzene, Guenet and coworkers 7,14 suggested that two different types of physical links are present in PVC gels: those between neat PVC crystallites and those within the PVC-solvent complex. They also found that the formation of a PVC-solvent complex commences above a specific PVC concentration of 1 3 10 À2 g cm À3 in diethyl oxalate, and is thermally reversible.…”

Section: Introductionmentioning

confidence: 99%

The effects of solvent type and aging on structural development in poly(vinyl chloride) thermoreversible gels

Hwang

Yang

Park

et al. 2007

J Polym Sci B Polym Phys

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We investigated the effects of solvent type (mono-ester vs. di-ester solvent) and aging on the structural development in the poly(vinyl chloride)/butyl benzoate (PVC/BB) and PVC/dibutyl phthalate(DBP) gels, as well as on their viscoelastic and mechanical behaviors. It was found that aged PVC/DBP gels held at RT for 7 days exhibit an improvement of about 100% in storage modulus (G 0 ) compared to fresh gels, with a sudden drop in G 0 around 50 8C, whereas the storage moduli of the PVC/BB gels decrease monotonically with temperature, irrespective of the postaging time. These different behaviors of the PVC/BB and PVC/DBP gels arise mainly because of the difference in the network structure produced by the formation of the polymer-solvent complex between the C¼ ¼O groups of the solvent and the polarized hydrogen moieties of PVC, as was confirmed with small angle X-ray scattering and uniaxial tensile experiments.

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Physical gels from PVC: dynamic properties of dilute solutions

Cited by 21 publications

References 13 publications

Thermoreversible lysozyme hydrogels: properties and an insight into the gelation pathway

Thermoreversible lysozyme hydrogels: properties and an insight into the gelation pathway

Solvent Effect on Structural Formation and Molecular Mobility of Polyvinyl Chloride Gels

The effects of solvent type and aging on structural development in poly(vinyl chloride) thermoreversible gels

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