Effects of Water-Soluble Spacers on the Hydrophobic Association of Fluorocarbon-Modified Poly(acrylamide)

Hwang, F. S.; Hogen‐Esch, Thieo E.

doi:10.1021/ma00113a037

Cited by 109 publications

(136 citation statements)

References 4 publications

Supporting

Mentioning

128

Contrasting

Order By: Relevance

“…13,26,29,32,51,76,92 In contrast, in the dilute regime, temperature-enhanced viscosity has been observed due to the disruption of the intramolecular interactions. 13,[92][93][94] In this study, we have investigated the effect of the temperature for the N7 sample well below the entanglement concentration (C ϭ 0.09 wt %; Fig. 9 and Table 2) and for the N3 polymer in the entangled regime (C ϭ 5 wt %; Table 2).…”

Section: Temperature Effect On the Viscoelastic Behaviormentioning

confidence: 99%

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Kujawa

Audibert‐Hayet

Selb

et al. 2004

J Polym Sci B Polym Phys

102

View full text Add to dashboard Cite

Multisticker associative polyelectrolytes of acrylamide (Ϸ86 mol %) and sodium 2-acrylamido-2-methylpropanesulfonate (Ϸ12 mol %), hydrophobically modified with N,N-dihexylacrylamide groups (Ϸ2 mol %), were prepared with a micellar radical polymerization technique. This process led to multiblock polymers in which the length of the hydrophobic blocks could be controlled through variations in the surfactant-tohydrophobe molar ratio, that is, the number of hydrophobes per micelle (N H ). The rheological behavior of aqueous solutions of polymers with the same molecular weight and the same composition but with two different hydrophobic block lengths (N H ϭ 7 or 3 monomer units per block) was investigated as a function of the polymer concentration with steady-flow, creep, and oscillatory experiments. The critical concentration at the onset of the viscosity enhancement decreased as the length of the hydrophobic segments in the polymers increased. Also, an increase in the N H value significantly enhanced the thickening ability of the polymers and affected the structure of the transient network.In the semidilute unentangled regime, the behavior of the polymer with long hydrophobic segments (N H ϭ 7) was studied in detail. The results were well explained by the sticky Rouse theory of associative polymer dynamics. Finally, the viscosity decreased with an increase in the temperature, mainly because of a lowering of the sample relaxation time.

show abstract

Section: Temperature Effect On the Viscoelastic Behaviormentioning

confidence: 99%

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Kujawa

Audibert‐Hayet

Selb

et al. 2004

J Polym Sci B Polym Phys

102

View full text Add to dashboard Cite

show abstract

“…Still, it is evident that the hydrophobized copolymer series 3a-3c and 4b-4c exhibit substantially lower t] ni values than poly-1 There is no indication of thickening effects as observed fo watersoluble copolymers with a very small fluorocarbon hydrophobe content [5][6][7][8][9][10][11]25]. Though effects due to strongly differing degrees of polymerization cannot be rigorously excluded as the molar masses are unknown, they are highly improbable as the polymerization conditions for the polymers were virtually identical.…”

Section: Viscosimetrymentioning

confidence: 99%

“…In particular, the use of fluorocarbon hydrophobic chains in polymers has so far been very limited. The few studies have been restricted basically to water-soluble polymers which are weakly substituted with fluorocarbon chains to provide efficient thickeners [5][6][7][8][9][10], or to block copolymers [11][12][13][14][15] or oligomers [16,17] respectively. Examples for water-soluble polymers which are heavily substituted with fluorocarbon chains, as needed for polysoaps to enable intramolecular aggregation, are virtually missing.…”

Section: Introductionmentioning

confidence: 99%

Polysoaps with fluorocarbon hydrophobic chains

1995

View full text Add to dashboard Cite

der scharffe Sebel ist mein Acker... U n i v e r s i t ä t P o t s d a mMathematisch-Naturwissenschaftliche Fakultät Abstract A series of amphiphilic copolymers is prepared by copolymerization of choline methacrylate with 1,1,2,2-tetrahydroperfluorooctyl methacrylate in varying amounts. The copolymers bearing fluorocarbon chains are studied concerning their effects on viscosity, solubilization and surface activity in aqueous solution, exhibiting a general behavior characteristic for polysoaps. The results are compared with the ones obtained for an analogous series of amphiphilic copolymers bearing hydrocarbon chains.

show abstract

“…One series of APs are based on poly(ethylene oxide) chains (referred to as PEO), being modified by short alkyl chains, [70][71][72][73][74]125 propyrene oxide (or butylene oxide) chains 77 and fluorocarbon chains. [78][79][80][81] Hydrophobes are either period-ically or randomly attached on a polymer chain. The simplest one is a telechelic polymer carrying two hydrophobes at the chain ends.…”

Section: Thermoreversible Gelation With Multiple Junctionsmentioning

confidence: 99%

Theoretical Study of Molecular Association and Thermoreversible Gelation in Polymers

Tanaka

2002

Polym J

View full text Add to dashboard Cite

ABSTRACT:This paper reviews our recent theoretical studies of molecular association and thermoreversible gelation in polymer solutions and blends. We first classify fundamental types of association, and propose their static and dynamic characterization. We then develope general theory of associating polymers to study phase transitions induced by molecular association. These transitions include macro-and microphase separation, micellization, hydration, thermoreversible gelation and liquid-crystalization. As for the origin of associative forces, we focus on hydrogen bonding and hydrophobic aggregation. Detailed study on thermoreversible gelation with multiple cross-link junctions is presented. Paying special attention to the multiplicity and sequence length of the network junctions, we derive phase diagrams with coexisting gelation and phase separation, and compare them with experimental data. Local and global structures of the gel networks are studied from molecular point of view. The theory is applied to more complex thermoreversible gels such as binary networks (interpenetrating networks, alternating networks and randomely mixed networks), hydrated networks with high-temperature gelation, gelation strongly coupled to polymer conformational transitions such as coil-to-helix transition. To study dynamics of thermoreversible gels, a simple transient network model is introduced, and creation and annihilation of junctions in the networks are theoretically described. Stationary non-linear viscosity and the dynamic mechanical moduli are calculated as functions of the shear rate, frequency and the chain disengagement rate. From the peak of the loss modulus, the lifetime τ × of the junction is estimated, and from the high frequency plateau of the storage modulus, the number of elastically effective chains in the network is found. Transient phenomena such as stress relaxation and stress overshoot are also theoretically studied. Results are compared with the recent experimental reports on the rheological study of hydrophobically modified water-soluble polymers.KEY WORDS Associating Polymers / Thermoreversible Gelation / Junction Multiplicity / Multicriticality / Transient Networks / Shear Thickening / Elastically Effective Chains / This paper reviews our recent theoretical studies of molecular association and thermoreversible gelation in polymer solutions. We introduce new theoretical frameworks to study phase transitions induced by association of polymer chains and dynamics of aggregation/dissociation processes.In most polymer blends or solutions, polymer chains carry active groups interacting with each other via strongly associative forces which are capable of forming temporal bonds. Hence description of the system in terms of van der Waals type contact energy -or χ-parameter in lattice theoretical terminology -is insufficient. These associative interactions include hydrogen bonding, ionic aggregation, electrostatic interaction, micro-crystallite formation, stereocomplex formation, solvent-complex formation, etc. Since ...

show abstract

Effects of Water-Soluble Spacers on the Hydrophobic Association of Fluorocarbon-Modified Poly(acrylamide)

Cited by 109 publications

References 4 publications

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Polysoaps with fluorocarbon hydrophobic chains

Theoretical Study of Molecular Association and Thermoreversible Gelation in Polymers

Contact Info

Product

Resources

About