Effect of Hydrophobization of Gold QCM-D Crystals on Surfactant Adsorption at the Solid-Liquid Interface

Knock, Mona Marie; Sanii, Laurie S.

doi:10.1021/bk-2011-1070.ch011

Cited by 5 publications

(4 citation statements)

References 35 publications

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“…[ 72 ] The knowledge of surfactant adsorption on hydrophilic surfaces is relevant to applications involving these minerals. The reported contact angle of the QCM-D gold sensors is only 11° [ 73 ], thus we selected the gold surface as a model hydrophilic surface to study rhamnolipid adsorption. The concentration of each pure rhamnolipid sample (0.15 wt.%) or P.R.…”

Section: Resultsmentioning

confidence: 99%

“…Similar to our study, irreversible adsorption occurred on the CPAC surface. Compared with R95D90 on gold, more rhamnolipid molecules remained on CPAC after rinsing; the possible reason being a higher affinity between the rhamnolipid molecules and the CPAC functional groups (information on the characterization was not reported in [ 73 ]). The ratio of Δ D /Δ f at equilibrium adsorption on CPAC was also calculated as an indication of the viscoelasticity of the equilibrium layer [ 74 ].…”

Section: Resultsmentioning

confidence: 99%

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Rhamnolipid Micellization and Adsorption Properties

Zhang

Placek

Jahan

et al. 2022

IJMS

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Biosurfactants are naturally occurring amphiphiles that are being actively pursued as alternatives to synthetic surfactants in cleaning, personal care, and cosmetic products. On the basis of their ability to mobilize and disperse hydrocarbons, biosurfactants are also involved in the bioremediation of oil spills. Rhamnolipids are low molecular weight glycolipid biosurfactants that consist of a mono- or di-rhamnose head group and a hydrocarbon fatty acid chain. We examine here the micellization of purified mono-rhamnolipids and di-rhamnolipids in aqueous solutions and their adsorption on model solid surfaces. Rhamnolipid micellization in water is endothermic; the CMC (critical micellization concentration) of di-rhamnolipid is lower than that of mono-rhamnolipid, and both CMCs decrease upon NaCl addition. Rhamnolipid adsorption on gold surface is mostly reversible and the adsorbed layer is rigid. A better understanding of biosurfactant self-assembly and adsorption properties is important for their utilization in consumer products and environmental applications.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Rhamnolipid Micellization and Adsorption Properties

Zhang

Placek

Jahan

et al. 2022

IJMS

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“…After washing, the zeta potential of the negatively charged nanoplatelets in the nanotriangle stock solution is −34 ± 1 mV. The negative zeta potential indicates that AOT micelles are adsorbed on the gold surface, − by analogy to adsorbed CTAB micelles on gold nanorods . Therefore, polycations can attach onto the negatively charged AOT layer, resulting in a reloading of the zeta potential.…”

Section: Results and Discussionmentioning

confidence: 99%

Undulated Gold Nanoplatelet Superstructures: In Situ Growth of Hemispherical Gold Nanoparticles onto the Surface of Gold Nanotriangles

Liebig¹,

Sarhan

Prietzel³

et al. 2018

Langmuir

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Negatively charged flat gold nanotriangles, formed in a vesicular template phase and separated by an AOT-micelle-based depletion flocculation, were reloaded by adding a cationic polyelectrolyte, that is, a hyperbranched polyethylenimine (PEI). Heating the system to 100 °C in the presence of a gold chloride solution, the reduction process leads to the formation of gold nanoparticles inside the polymer shell surrounding the nanoplatelets. The gold nanoparticle formation is investigated by UV-vis spectroscopy, small-angle X-ray scattering, and dynamic light scattering measurements in combination with transmission electron microscopy. Spontaneously formed gold clusters in the hyperbranched PEI shell with an absorption maximum at 350 nm grow on the surface of the nanotriangles as hemispherical particles with diameters of ∼6 nm. High-resolution micrographs show that the hemispherical gold particles are crystallized onto the {111} facets on the bottom and top of the platelet as well as on the edges without a grain boundary. Undulated gold nanoplatelet superstructures with special properties become available, which show a significantly modified performance in SERS-detected photocatalysis regarding both reactivity and enhancement factor.

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“…Quartz crystal microbalance with dissipation monitoring (QCM-D) is an extremely versatile technique that has gained considerable traction in practically every experimental field. By resolving real-time mass changes of thin films with ng/cm 2 resolution and by determining film mechanical properties (e.g., modulus and viscosity), QCM-D has been used to study nanoparticle adsorption interactions − and tribology, , water-uptake dynamics in ion-conducting polymers, − gas absorption into a variety of materials, − polymer brush conformation changes and swelling in response to stimuli, − polymer, − surfactant, − and asphaltene adsorption, − electrode formation , and properties under applied potential, − enzymatic deconstruction kinetics of cellulose, adsorption through wetting films, and as a biosensing technique for virus , and bacteria − detection and biomarker monitoring, − among many other applications. Extensive reviews and textbooks are available. − A majority of the above references focus on the subject of this work: the use of QCM-D to study solution adsorption of, for example, solvent-dissolved surfactants, polymers, and colloidal particles.…”

Section: Introductionmentioning

confidence: 99%

A Two-Phase Model for Adsorption from Solution Using Quartz Crystal Microbalance with Dissipation

et al. 2022

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Quartz crystal microbalance with dissipation (QCM-D) conveniently monitors mass and mechanical property changes of thin films on solid substrates with exquisite resolution. QCM-D is frequently used to measure dissolved solute/sol adsorption isotherms and kinetics. Unfortunately, currently available methodologies to interpret QCM-D data treat the adlayer as a homogeneous medium, which does not adequately describe solution-adsorption physics. Tethering of the adsorbate to the solid surface is not explicitly recognized, and the liquid solvent is included in the adsorbate mass, which is especially in error for low coverages. Consequently, the areal mass of adsorbate (i.e., solute adsorption) is overestimated. Further, friction is not considered between the bound adsorbate and the free solvent flowing in the adlayer. To overcome these deficiencies, we develop a two-phase (2P) continuum model that self-consistently determines adsorbate and liquid–solvent contributions and includes friction between the attached adsorbate and flowing liquid solvent. We then compare the proposed 2P model to those of Sauerbrey for a rigid adlayer and Voinova et al. for a viscoelastic-liquid adlayer. Effects of 2P-adlayer properties are examined on QCM-D-measured frequency and dissipation shifts, including adsorbate volume fraction and elasticity, adlayer thickness, and overtone number, thereby guiding data interpretation. We demonstrate that distinguishing between adsorbate adsorption and homogeneous-film adsorption is critical; failing to do so leads to incorrect adlayer mass and physical properties.

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Effect of Hydrophobization of Gold QCM-D Crystals on Surfactant Adsorption at the Solid-Liquid Interface

Cited by 5 publications

References 35 publications

Rhamnolipid Micellization and Adsorption Properties

Rhamnolipid Micellization and Adsorption Properties

Undulated Gold Nanoplatelet Superstructures: In Situ Growth of Hemispherical Gold Nanoparticles onto the Surface of Gold Nanotriangles

A Two-Phase Model for Adsorption from Solution Using Quartz Crystal Microbalance with Dissipation

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