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Surface deposition and phase behavior of oppositely charged polyion-surfactant ion complexes. Delivery of silicone oil emulsions to hydrophobic and hydrophilic surfaces.

Clauzel M, Johnson ES, Nylander T, Panandiker RK, Sivik MR, Piculell L - ACS Appl Mater Interfaces (2011)

Bottom Line: The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl.The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers.For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high.

View Article: PubMed Central - PubMed

Affiliation: Physical Chemistry, Kemicentrum, Lund University, Box 124, SE-221 00, Lund, Sweden. maryline.clauzel@gmail.com

ABSTRACT
The adsorption from mixed polyelectrolyte-surfactant solutions at hydrophobized silica surfaces was investigated by in situ -ellipsometry, and compared to similar measurements for hydrophilic silica surfaces. Three synthetic cationic copolymers of varying hydrophobicity and one cationic hydroxyethyl cellulose were compared in mixtures with the anionic surfactant sodium dodecylsulfate (SDS) in the absence or presence of a dilute silicone oil emulsion. The adsorption behavior was mapped while stepwise increasing the concentration of SDS to a polyelectrolyte solution of constant concentration. The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl. An adsorbed layer remained after complete exchange of the polyelectrolyte/surfactant solution for aqueous NaCl. In most cases, there was a codeposition of silicone oil droplets, if such droplets were present in the formulation before dilution. The overall features of the deposition were similar at hydrophobic and hydrophilic surfaces, but there were also notable differences. SDS molecules adsorbed selectively at the hydrophobized silica surface, but not at the hydrophilic silica, which influenced the coadsorption of the cationic polymers. The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers. For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high.

No MeSH data available.


Related in: MedlinePlus

Schematic representation of the automated Rudolph Research thin-film  ellipsometer type 43603–200E. The method is based on measurement of the changes in the state of polarization of light. The polarized light from the laser is depolarized with a circular polarizer. After the polarizer, the emerging linearly polarized light is transformed into elliptically polarized light when passing through the compensator, which is a quarter wave plate. The ellipticity can be varied by rotating the polarizer. As the reflection against the surface of the sample also changes the ellipticity of the light, the polarizer can be rotated in such a way that the light after reflection again is linearly polarized. The relative rotation of this light is measured by using another polarizer, the analyzer, which is rotated until a minima in light intensity as measured by the detector.
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fig2: Schematic representation of the automated Rudolph Research thin-film ellipsometer type 43603–200E. The method is based on measurement of the changes in the state of polarization of light. The polarized light from the laser is depolarized with a circular polarizer. After the polarizer, the emerging linearly polarized light is transformed into elliptically polarized light when passing through the compensator, which is a quarter wave plate. The ellipticity can be varied by rotating the polarizer. As the reflection against the surface of the sample also changes the ellipticity of the light, the polarizer can be rotated in such a way that the light after reflection again is linearly polarized. The relative rotation of this light is measured by using another polarizer, the analyzer, which is rotated until a minima in light intensity as measured by the detector.

Mentions: This technique is based on measurements of changes in the state of polarization when polarized light is reflected against a surface, given by the relative change in amplitude, Ψ, and phase shift, Δ. The measured parameters, Ψ and Δ, can be used to calculate the thickness and the refractive index of a layer formed on a macroscopic surface. From these two parameters the adsorbed amount of a material can be calculated. In this study we used an automated Rudolph Research thin-film ellipsometer type 43603–200E, where the light first passes a polarizer followed by a quarter wave plate (compensator) and then is reflected against the sample. Finally, after passing another polarizer (analyzer), the light intensity is monitored with a detector as shown in Figure 2. A xenon arc lamp was used as the light source and a filter for a wavelength of 401.5 nm was placed just before the detector. The measurements were performed at an angle of incidence of 68°, using a trapezoid glass cuvette with a sample volume of about 5 mL. The solution in the cuvette was agitated by means of a magnetic stirrer at a speed of 300 rpm. Continuous exchange of the bulk solution (dilution or “rinse” experiment) was achieved by means of two Teflon tubes, which were inserted into the cuvette and connected to a multichannel peristaltic pump set at a flow rate of 5 mL/min. The inlet to the cuvette was connected to a container with salt or SDS solution and the outlet from the cuvette was connected to the drain. All experiments were performed at 25 ± 0.1 °C, the temperature being regulated by a thermostatted bath. The setup allows measurements with a time resolution of 2–3 s.


Surface deposition and phase behavior of oppositely charged polyion-surfactant ion complexes. Delivery of silicone oil emulsions to hydrophobic and hydrophilic surfaces.

Clauzel M, Johnson ES, Nylander T, Panandiker RK, Sivik MR, Piculell L - ACS Appl Mater Interfaces (2011)

Schematic representation of the automated Rudolph Research thin-film  ellipsometer type 43603–200E. The method is based on measurement of the changes in the state of polarization of light. The polarized light from the laser is depolarized with a circular polarizer. After the polarizer, the emerging linearly polarized light is transformed into elliptically polarized light when passing through the compensator, which is a quarter wave plate. The ellipticity can be varied by rotating the polarizer. As the reflection against the surface of the sample also changes the ellipticity of the light, the polarizer can be rotated in such a way that the light after reflection again is linearly polarized. The relative rotation of this light is measured by using another polarizer, the analyzer, which is rotated until a minima in light intensity as measured by the detector.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211372&req=5

fig2: Schematic representation of the automated Rudolph Research thin-film ellipsometer type 43603–200E. The method is based on measurement of the changes in the state of polarization of light. The polarized light from the laser is depolarized with a circular polarizer. After the polarizer, the emerging linearly polarized light is transformed into elliptically polarized light when passing through the compensator, which is a quarter wave plate. The ellipticity can be varied by rotating the polarizer. As the reflection against the surface of the sample also changes the ellipticity of the light, the polarizer can be rotated in such a way that the light after reflection again is linearly polarized. The relative rotation of this light is measured by using another polarizer, the analyzer, which is rotated until a minima in light intensity as measured by the detector.
Mentions: This technique is based on measurements of changes in the state of polarization when polarized light is reflected against a surface, given by the relative change in amplitude, Ψ, and phase shift, Δ. The measured parameters, Ψ and Δ, can be used to calculate the thickness and the refractive index of a layer formed on a macroscopic surface. From these two parameters the adsorbed amount of a material can be calculated. In this study we used an automated Rudolph Research thin-film ellipsometer type 43603–200E, where the light first passes a polarizer followed by a quarter wave plate (compensator) and then is reflected against the sample. Finally, after passing another polarizer (analyzer), the light intensity is monitored with a detector as shown in Figure 2. A xenon arc lamp was used as the light source and a filter for a wavelength of 401.5 nm was placed just before the detector. The measurements were performed at an angle of incidence of 68°, using a trapezoid glass cuvette with a sample volume of about 5 mL. The solution in the cuvette was agitated by means of a magnetic stirrer at a speed of 300 rpm. Continuous exchange of the bulk solution (dilution or “rinse” experiment) was achieved by means of two Teflon tubes, which were inserted into the cuvette and connected to a multichannel peristaltic pump set at a flow rate of 5 mL/min. The inlet to the cuvette was connected to a container with salt or SDS solution and the outlet from the cuvette was connected to the drain. All experiments were performed at 25 ± 0.1 °C, the temperature being regulated by a thermostatted bath. The setup allows measurements with a time resolution of 2–3 s.

Bottom Line: The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl.The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers.For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high.

View Article: PubMed Central - PubMed

Affiliation: Physical Chemistry, Kemicentrum, Lund University, Box 124, SE-221 00, Lund, Sweden. maryline.clauzel@gmail.com

ABSTRACT
The adsorption from mixed polyelectrolyte-surfactant solutions at hydrophobized silica surfaces was investigated by in situ -ellipsometry, and compared to similar measurements for hydrophilic silica surfaces. Three synthetic cationic copolymers of varying hydrophobicity and one cationic hydroxyethyl cellulose were compared in mixtures with the anionic surfactant sodium dodecylsulfate (SDS) in the absence or presence of a dilute silicone oil emulsion. The adsorption behavior was mapped while stepwise increasing the concentration of SDS to a polyelectrolyte solution of constant concentration. The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl. An adsorbed layer remained after complete exchange of the polyelectrolyte/surfactant solution for aqueous NaCl. In most cases, there was a codeposition of silicone oil droplets, if such droplets were present in the formulation before dilution. The overall features of the deposition were similar at hydrophobic and hydrophilic surfaces, but there were also notable differences. SDS molecules adsorbed selectively at the hydrophobized silica surface, but not at the hydrophilic silica, which influenced the coadsorption of the cationic polymers. The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers. For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high.

No MeSH data available.


Related in: MedlinePlus