Ellipsometric studies of nonionic block copolymers adsorbed at the solid/water and oil/water interfaces

Kapilashrami, Abha; Malmsten, Martin; Eskilsson, Krister; Benjamins, J.; Nylander, Tommy

doi:10.1016/s0927-7757(03)00361-3

Cited by 16 publications

(22 citation statements)

References 29 publications

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“…PEO star polymers adsorbed in single-shot experiments showed a high affinity adsorption isotherm on silica, with a plateau surface excess concentration of approximately 2.7 ± 0.15 mg/m 2 , whereas the high molecular weight linear PEO adsorption maximum was approximately 0.7 ± 0.04 mg/m 2 . The latter is consistent with literature values for high molecular weight PEO adsorption to silica. − The PEO arms account for approximately 80 wt % of the star structure, so 2.7 mg/m 2 corresponds to a surface excess concentration of approximately 2.2 mg/m 2 of PEO, which is still three times the amount of PEO adsorption achieved by the linear polymer. This enhancement of PEO adsorption does not happen with amphiphilic, PEO-containing nonionic block copolymers on silica in water, as noted above …”

Section: Resultssupporting

confidence: 90%

Poly(Ethylene Oxide) Star Polymer Adsorption at the Silica/Aqueous Interface and Displacement by Linear Poly(Ethylene Oxide)

Saigal¹,

Riley²,

Golas³

et al. 2013

Langmuir

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Multiarm star copolymers with approximately 460 poly(ethylene oxide) (PEO) arms that have a degree of polymerization N = 45 were synthesized via atom transfer radical polymerization (ATRP) of PEO-methacrylate macromonomers in the presence of divinyl benzene cross-linkers. These are an example of molecular or nanoparticulate brushes that are of interest as steric stabilizers or boundary lubrication agents when adsorbed from solution to a solid/aqueous interface. We use ellipsometry to measure adsorption isotherms at the silica/aqueous interface for PEO star polymers and linear PEO chains having molecular weights comparable either to the star polymer or to the individual arms. The compactness of the PEO star polymers (molecular weight 1.2 × 10(6)) yields a saturation surface excess concentration that is approximately 3.5 times greater than that of the high molecular weight (1 × 10(6)) linear PEO. Adsorption of low molecular weight (6000) linear PEO was below the detection limit. Competitive adsorption experiments were conducted with ellipsometry, complemented by independent quartz crystal microbalance with dissipation (QCM-D) measurements. Linear PEO (high molecular weight) displaced preadsorbed PEO star polymers over the course of approximately 1.5 h, to form a mixed adsorbed layer having not only a significantly lower overall polymer surface excess concentration, but also a significantly greater amount of hydrodynamically entrapped water. Challenging a preadsorbed linear PEO (high molecular weight) layer with PEO star polymers produced no measurable change in the overall polymer surface excess concentration, but changes in the QCM-D energy dissipation and resonance frequency suggested that the introduction of PEO star polymers caused a slight swelling of the layer with a correspondingly small increase in entrapped water content.

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Section: Resultssupporting

confidence: 90%

Poly(Ethylene Oxide) Star Polymer Adsorption at the Silica/Aqueous Interface and Displacement by Linear Poly(Ethylene Oxide)

Saigal¹,

Riley²,

Golas³

et al. 2013

Langmuir

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“…The areas occupied by one molecule are close to the values reported earlier for PE10500, i.e., 4.0 nm 2 [13], and for PE6800, i.e., 8.7 nm 2 [9], and roughly follow the order of molecular weight of the Pluronics. These adsorption results indicated that the order of the adsorption ability of the Pluronics examined in the present study on a hydrophobic solid surface is PE10300 >> PE10500 $ PE6400 > PE6800.…”

Section: Adsorption Measured By Owlssupporting

confidence: 88%

“…Due to the biocompatible character of PEO-containing coatings applied to various biomaterials, interest has focused on the properties of adsorbed Pluronic layers and their role in reducing nonspecific protein adsorption and cell adhesion on biomaterial surfaces [4À7]. The interfacial adsorption behavior of block copolymer surfactants from solutions has been extensively studied [8,9]. Their amphiphilic nature arises from the different solubilities of the copolymer blocks.…”

mentioning

confidence: 99%

Adsorption and Wetting Properties of Pluronic Block Copolymers on Hydrophobic Surfaces Studied by Optical Waveguide Lightmode Spectroscopy and Dynamic Tensiometric Method

Kiss

Erdélyi

Szendrő

et al. 2004

The Journal of Adhesion

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Adsorption of four different poly(ethylene oxide)=poly(propylene oxide)=poly (ethylene oxide) triblock copolymers (Pluronics 1 ) onto the hydrophobized surface of the sensor was measured by the optical waveguide lightmode spectroscopy (OWLS). Adsorbed amounts of Pluronic PE10300, PE10500, PE6400, and PE6800 determined in the concentration range of 10 À2 À10 gdm À3 were found to follow the order of the hydrophobicity of the Pluronic compounds characterized by their hydrophilÀlipophil balance (HLB) values. Wettability of two hydrophobic surfaces, the poly(lactide-co-glycolide), PLGA70=30 copolymer (used as drug carrier in pharmaceutical applications) and silylated glass, in aqueous solutions of the above Pluronics were studied by a dynamic tensiometric method. The significant increase in the wetting tension observed after the adsorption of the surfactants, and hence the decrease of the apparent contact angle as the indication of the wetting effect on both the biopolymer and the hydrophobic glass, was correlated to the poly(ethylene oxide) (PEO) content of the adsorbed layer obtained on the hydrophobized sensor surface by the OWLS method.

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“…Assuming a saturated surface area per molecule of 1.44 nm 2 for PF68 (i.e., 1.03 × 10 20 nm 2 · g −1 ),24 in a good agreement with results reported by Alexandridis et al,25 the surface coverage, A S , by the polymer surfactant could be estimated as 7.4 nm 2 if using PF68 alone. Some higher values of the surface area per molecule have also been reported for PF68, namely 5.323 and 8.7 nm 2 26. These values seem too high with respect to the values reported for the other copolymers in order to agree with the N

_{EO}^{1/2}

dependence, but using the highest value, however, leads to a theoretical A S / A P (where A P is the surface area of the particles) ratio of around unity.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of New Cellobiose‐Based Glycopolysiloxanes and their Use as Polymer Stabilizers in Miniemulsion Polymerisation

Berson

Viet

Halila

et al. 2008

Macro Chemistry & Physics

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New glycopolysiloxanes were synthesized from cellobiose and commercially available reactive silicone oils or MD′M precursors. Their synthesis is based on the hydrosilylation of allyl‐functionalized cellobiose onto the reactive silicone oil, after protection of the hydroxyl functions. The subsequent deprotection step leads to a redistribution of the silicon chain to yield oligomers with around 5 or 6 silicon atoms. Two water‐dispersible glycosiloxanes were used for the steric stabilisation of vinyl acetate (VAc) miniemulsion polymerisation with up to 10% Miglyol® as the hydrophobic component. The best performances were obtained by using a mixture of non‐ionic triblock copolymer and glycopolysiloxane. Poly(vinyl acetate) (PVAc) latex with particle sizes around 200 nm were obtained, displaying colloidal stabilisation upon long‐time storage.

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Ellipsometric studies of nonionic block copolymers adsorbed at the solid/water and oil/water interfaces

Cited by 16 publications

References 29 publications

Poly(Ethylene Oxide) Star Polymer Adsorption at the Silica/Aqueous Interface and Displacement by Linear Poly(Ethylene Oxide)

Poly(Ethylene Oxide) Star Polymer Adsorption at the Silica/Aqueous Interface and Displacement by Linear Poly(Ethylene Oxide)

Adsorption and Wetting Properties of Pluronic Block Copolymers on Hydrophobic Surfaces Studied by Optical Waveguide Lightmode Spectroscopy and Dynamic Tensiometric Method

Synthesis of New Cellobiose‐Based Glycopolysiloxanes and their Use as Polymer Stabilizers in Miniemulsion Polymerisation

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