2002
DOI: 10.1007/3-540-45823-9_25
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Dynamics of Hydrophobically Modified Polymer Doped Surfactant Bilayers: A Neutron Spin Echo Study

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Cited by 5 publications
(11 citation statements)
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“…A coverage ≈ # chains volume blobs chain area blob In this study, a model proposed by Nallet et al 35 was used to obtain η, d, and δ, with the details addressed elsewhere. 7,36 The Caille ´constant η and the interlamellar distance d are extracted from the structure factor S(q), while form factor P(q) yields the membrane thickness δ. The fitted membrane thickness δ of 24 ( 2 Å remains unchanged for all the samples studied, which is consistent with our previous observation.…”
Section: Resultsmentioning
confidence: 99%
“…A coverage ≈ # chains volume blobs chain area blob In this study, a model proposed by Nallet et al 35 was used to obtain η, d, and δ, with the details addressed elsewhere. 7,36 The Caille ´constant η and the interlamellar distance d are extracted from the structure factor S(q), while form factor P(q) yields the membrane thickness δ. The fitted membrane thickness δ of 24 ( 2 Å remains unchanged for all the samples studied, which is consistent with our previous observation.…”
Section: Resultsmentioning
confidence: 99%
“…Plotting q 4 I(q) highlights the maximum in form factor (once the incoherent background scattering has been subtracted), from which we estimate a bilayer thickness δ ) 24 ( 2 Å that is independent of polymer molecular weight, polydispersity, and polymer concentration. 39 The compressibility of the membrane stack is reflected in the low q behavior of the structure factor S(q) obtained from the experimental scattering intensity I(q) from eq 6. The structure factor S(q), form factor P(q), and scattering intensity I(q) are shown in Figure 4.…”
Section: Neutron Scattering Studies Of Membrane Propertiesmentioning
confidence: 99%
“…The permeability of the PAA layer can be estimated by D ∼ η L /(2.1 × 10 12 ω 3/2 ), with ω being the mass fraction of polymer in the brush layer . The Young's modulus E is related to the bending modulus κ by κ = E δ 3 /12(1 − ν m 2 ), where ν m is the Poisson ratio of the surfactant membrane, which is ∼0.5 assuming the membrane is incompressible. , For the hmPEG-doped membrane system at φ = 0.3 and C p = 2 wt %, the estimated hydrodynamic relaxation time τ hyd for solvent to flow through the polymer layer is ∼900 ns, assuming the bending modulus κ ∼ 1 k B T . ,, This time scale is again comparable to that of the relaxation of polymer-doped membranes, which supports the hypothesis of slowed dynamics due to viscous dissipation in the adsorbed polymer layer.
8 The measured values of d φ vs ln φ over the whole dilution range for (a) the hmPAA systems with different surface coverages and (b) the hmPEG system.
…”
Section: Resultsmentioning
confidence: 97%
“…At this point, we propose the following physical model. There are two possibilities for the “speeding up”: (1) Polymers make the membrane stiffer, ,, and therefore the relaxations are faster (as predicted from the dispersion relation for membrane undulations, Γ q ∝ κ , ) (Figure a). (2) There is a coupling between lateral polymer diffusion on the membrane surface and the relaxation of undulations in the low surface coverage case.…”
Section: Resultsmentioning
confidence: 99%