Solvent effects on aggregation behavior of polyvinyl alcohol solutions

Hong, Po‐Da; Chou, Che-Min; He, Chiu‐Hui

doi:10.1016/s0032-3861(01)00056-8

Cited by 98 publications

(70 citation statements)

References 46 publications

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“…Here the first moment over the end-point distribution of both the PEO as well as the PVOH polymers, h g , is plotted versus v PVOH-W. In panels c-f the volume fraction profiles u(x,z) for PEO and PVOH are shown for a special case: v PEO-PVOH = 0.4 and v PVOH-W = 0.52 potentially resembling the experimental situation, as described above, where the solvent quality of PVOH is marginal, that of PEO is slightly better, and PEO and PVOH are rather incompatible [37,44,45]. Note that we purposely neglected potential disparities in surface affinity et cetera, as they are, to the best of our knowledge, not known for the system.…”

Section: Self-consistent Field Calculationsmentioning

confidence: 83%

“…We might speculate that these aggregates originate from the rather poor solubility of PVOH [37,38] or from interpolymer complexation between PVOH/PEO and PAA chains which is known to yield insoluble complexes under more acidic conditions; that is, pH <4 [39,40]. Khutoryanskiy et al [39,41] It has also been reported that water is only a marginal solvent for PVOH [37], and aggregation was observed in dilute aqueous solutions of PVOH homopolymers [38]. Note, however, that the marginally soluble vinyl alcohol monomers constitute only a minor part (614%) of the micellar corona.…”

Section: Micellar Structurementioning

confidence: 99%

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Electrostatic hierarchical co-assembly in aqueous solutions of two oppositely charged double hydrophilic diblock copolymers

Voets¹,

Keizer²,

Leermakers³

et al. 2009

European Polymer Journal

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The formation of spherical micelles in aqueous solutions of poly(N-methyl-2-vinyl pyridinium iodide)-block-poly(ethylene oxide), P2MVP-b-PEO and poly(acrylic acid)-block-poly (vinyl alcohol), PAA-b-PVOH has been investigated with light scattering-titrations, dynamic and static light scattering, and 1 H 2D Nuclear Overhauser Effect Spectroscopy. Complex coacervate core micelles, also called PIC micelles, block ionomer complexes, and interpolyelectrolyte complexes, are formed in thermodynamic equilibrium under charge neutral conditions (pH 8, 1 mM NaNO 3 , T = 25°C) through electrostatic interaction between the core-forming P2MVP and PAA blocks. 2D 1 H NOESY NMR experiments show no cross-correlations between PEO and PVOH blocks, indicating their segregation in the micellar corona. Self-consistent field calculations support the conclusion that these C3Ms are likely to resemble a 'patched micelle'; that is, micelles featuring a 'spheres-on-sphere' morphology.

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Section: Self-consistent Field Calculationsmentioning

confidence: 83%

Section: Micellar Structurementioning

confidence: 99%

Electrostatic hierarchical co-assembly in aqueous solutions of two oppositely charged double hydrophilic diblock copolymers

Voets¹,

Keizer²,

Leermakers³

et al. 2009

European Polymer Journal

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“…Before drying, Hong et al reported that each fully hydrolyzed PVA molecule forms a tightly aggregated structure due to intramolecular hydrogen bonding, resulting in a solution with little to no elasticity. 13 However, as drying proceeds, the intermolecular separation becomes small enough that the hydrogen bonding between PVA molecules may become significant. In any case, an increased fraction of the remaining water molecules are also associated via molecular bonding with the polymer, which may decrease the average water mobility enough to affect the transport of water to the interface.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Hong et al also reported that fully hydrolyzed PVA in water has a very small excluded volume due to strong intramolecular hydrogen bonding. 13 On the other hand, the large number of acetate groups contained in the less hydrolyzed PVA weakens the inter/intra hydrogen bonding, and this leads to a more expanded than the fully hydrolyzed DH = 100 PVA.…”

Section: ■ Materialsmentioning

confidence: 99%

Local, Real-Time Measurement of Drying Films of Aqueous Polymer Solutions Using Active Microrheology

2014

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Local, real-time measurement of drying films of aqueous polymer solutions using active microrheology ABSTRACT: Oscillatory microdisk rheometry was applied to evaluate the evolution of the viscoelastic properties at the surface of a film of an aqueous solution of poly(vinyl alcohol) (PVA) during drying. The drying rate was measured concurrently, based upon measurements of the variation of film thickness. A fully hydrolyzed PVA solution shows a constant drying rate, while a less hydrolyzed PVA solution exhibits a decreased drying rate in the latter part of the drying process, which occurred at the same time as an increase of the elastic modulus. We suggest that this difference in behavior is a consequence of the fact that both the configuration of the PVA molecule and the strength of interaction with water depend on the degree to which the PVA is hydrolyzed. The polymer concentration at the film surface can be estimated from the measured viscosity at the surface for the fully hydrolyzed PVA solution, and this result then can be compared with two theoretical calculations: one in which the polymer concentration is assumed to remain uniform throughout the film, and the other in which the polymer concentration distribution is determined via a one-dimensional diffusion model. This comparison suggests that the polymer is first concentrated locally near the surface but later in the drying process the distribution of polymer becomes increasingly uniform, possibly due to a spontaneously generated convective flow inside the film.

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“…An innovative synthesis method was used to synthesize PVA/p(AAmNIPAm) nanogels in an aqueous system. The objective of this work is to develop PVA/p(AAm-NIPAm) core-shell hydrogels nanoparticle with different mole ratios of copolymerized (AAm-NIPAm) with respect to the amount of PVA as a potential effective adsorbents to remove Cu +2 from aqueous solution attributing to their following unique properties: (i) PVA core is a hydrophilic macromolecule and readily dissolves in water, so that the dynamic behavior of PVA polymer chain is highly sensitive to the solvent quality in a dilute solution [14], so used as solid carriers afford mechanic strength to enhance the usable life. (ii) pNIPAm hydrogel swollen in water is a typical temperature-sensitive hydrogel that exhibits a volume phase transition (VPT) in response to temperature changes at around 33°C [15].…”

Section: Introductionmentioning

confidence: 99%

Adsorption Characteristics of Copper (II) Ions from Aqueous Solution onto Ionic Cross-linked Pva/P(Aam-Nipaam) Core-shell Nanogels

Sarhan¹

2015

J Nanomed Nanotechnol

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Core-shell nanogels adsorbent were investigated for copper (II) removal from aqueous solution, consisting of poly(vinyl alcohol) (PVA) core and poly(acrylamide-N-isopropylacrylamide/) p(AAm-NIPAm) shell particles. Various factors affecting the adsorption capacity, such as swelling, pH, time, initial ion concentration, and different metal ions on the metal ion binding capacity for nanogel, was also tested. The selectivity of the nanogels toward the different metal ions tested was Cu 2+ > N i2+ > Pb 2+ . The results show that the adsorption of nanogels mainly depends on pH, and the maximum adsorption was obtained at a pH of 6.0. The adsorption capacity of Cu +2 was 126 mg/g obtained under simple and fast experimental conditions, the effect of different mole ratios of p(AAm-NIPAm) shells thickness were synthesized, to determine the maximum metal uptake. The core-shell nanogels were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and transmission electron microscope (TEM). It was found that adsorbed Cu +2 ions on PVA/p(AAm-NIPAm) nanogels can be effectively desorbed by acid stripping with 0.1 mol/L HCl resulted in 96% Cu +2 recovery for the nanogels; this shows the ability of the nanogels to be reused, upon drying between treatments. The nanogels adsorbent can be regenerated after releasing of Cu +2 and reused three times effectively. All the experimental result exhibited good matches with the Freundlich isotherm and followed pseudo-second-order kinetics. The mechanism of adsorption of Cu +2 onto PVA/p(AAm-NIPAm) nanogels is proposed.

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Solvent effects on aggregation behavior of polyvinyl alcohol solutions

Cited by 98 publications

References 46 publications

Electrostatic hierarchical co-assembly in aqueous solutions of two oppositely charged double hydrophilic diblock copolymers

Electrostatic hierarchical co-assembly in aqueous solutions of two oppositely charged double hydrophilic diblock copolymers

Local, Real-Time Measurement of Drying Films of Aqueous Polymer Solutions Using Active Microrheology

Adsorption Characteristics of Copper (II) Ions from Aqueous Solution onto Ionic Cross-linked Pva/P(Aam-Nipaam) Core-shell Nanogels

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