AFM forces between mica and polystyrene surfaces in aqueous electrolyte solutions with and without gas bubbles

Saavedra, Jorge H.; Acuña, Sergio; Toledo, Pedro G.

doi:10.1016/j.jcis.2013.08.001

Cited by 9 publications

(4 citation statements)

References 55 publications

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“…This repulsion increases with increasing compression of the polymeric layer. It is well-known that PS surfaces are not strictly neutral because they possess negative residual charges [38–40]. …”

Section: Resultsmentioning

confidence: 99%

Direct measurement of interaction forces between bovine serum albumin and poly(ethylene oxide) in water and electrolyte solutions

2017

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The net interaction between a probe tip coated with bovine serum albumin (BSA) protein and a flat substrate coated with poly(ethylene oxide) (PEO) polymer was measured directly on approach in water and electrolyte solutions using AFM. The approach force curve between the two surfaces was monotonically repulsive in water and in electrolyte solutions. At pH ~5, slightly above the isoelectric point (pI) of BSA, and at large distances, the force was dominated by electrostatic repulsion between the oxygen atoms of the incoming protein with those belonging to the ether groups of PEO. Such repulsive force and range decreased in NaCl. Under physiological conditions, pH 6, BSA is definitely charged and the electrostatic repulsion with ether groups in PEO appears at larger separation distances. Interestingly, at pH 4, below the pI of BSA, the repulsion decreased because of an attractive, although weak, electrostatic force that appeared between the ether groups in PEO and the positively charged amino groups of BSA. However, for all solution conditions, once compression of PEO begun, the net repulsion was always dominated by short-range polymeric steric repulsion and repulsive enthalpy penalties for breaking PEO-water bonds. Results suggest that PEO in mushroom conformation may also be effective in reducing biofouling.

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Section: Resultsmentioning

confidence: 99%

Direct measurement of interaction forces between bovine serum albumin and poly(ethylene oxide) in water and electrolyte solutions

2017

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“…Bram et al reported that the nanobubbles on polyamide and hydrophobized silicon surfaces not only are stable under ambient conditions but also exhibit superstability under reduced pressure in cavitation experiments . Also, the presence of bubbles on the material surfaces affects the hydrophobic interaction between mica and polystyrene . Ehrenhauser et al demonstrated that bubble bursting as an aerosol generation mechanism during an oil spill in the deep-sea environment was a pathway for the transport of alkanes into the atmosphere .…”

Section: Introductionmentioning

confidence: 99%

“…25 Also, the presence of bubbles on the material surfaces affects the hydrophobic interaction between mica and polystyrene. 26 Ehrenhauser et al demonstrated that bubble bursting as an aerosol generation mechanism during an oil spill in the deep-sea environment was a pathway for the transport of alkanes into the atmosphere. 27 Adsorption of some chemicals (especially surfactants) on air bubbles has been widely reported, 28,29 but the effect of air bubbles on pollutant adsorption on adsorbents has hardly been studied to date.…”

Section: ■ Introductionmentioning

confidence: 99%

Role of Air Bubbles Overlooked in the Adsorption of Perfluorooctanesulfonate on Hydrophobic Carbonaceous Adsorbents

Meng

Deng

et al. 2014

Environ. Sci. Technol.

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Hydrophobic interaction has been considered to be responsible for adsorption of perfluorooctanesulfonate (PFOS) on the surface of hydrophobic adsorbents, but the long C-F chain in PFOS is not only hydrophobic but also oleophobic. In this study, for the first time we propose that air bubbles on the surface of hydrophobic carbonaceous adsorbents play an important role in the adsorption of PFOS. The level of adsorption of PFOS on carbon nanotubes (CNTs), graphite (GI), graphene (GE), and powdered activated carbon (PAC) decreases after vacuum degassing. Vacuum degassing time and pressure significantly affect the removal of PFOS by these adsorbents. After vacuum degassing at 0.01 atm for 36 h, the extent of removal of PFOS by the pristine CNTs and GI decreases 79% and 74%, respectively, indicating the main contribution of air bubbles to PFOS adsorption. When the degassed solution is recontacted with air during the adsorption process, the removal of PFOS recovers to the value obtained without vacuum degassing, further verifying the key role of air bubbles in PFOS adsorption. By theoretical calculation, the distribution of PFOS in air bubbles on the adsorbent surfaces is discussed, and a new schematic sorption model of PFOS on carbonaceous adsorbents in the presence of air bubbles is proposed. The accumulation of PFOS at the interface of air bubbles on the adsorbents is primarily responsible for its adsorption, providing a new mechanistic insight into the transport, fate, and removal of PFOS.

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“…Another parameter is the roughness of the particle surface which also plays a crucial role for the pH depending adhesion as depicted by Toikka et al 34 Additionally, hydrophobic forces can play a role because the hydrophilicity of silicon dioxide changes with the pH value of the water solution. 35 It was also demonstrated that the concentration of electrolytes 36,37 and the presence of gas bubbles 38 in the solution affects the electrostatic long-range forces and adhesion at the interface. To quantitatively distinguish between the contributions of the above-mentioned physiochemical effects to the adhesion force, however, it is not straight forward and is subject to further studies.…”

Section: Manipulation Process and Contact Mechanics Modelmentioning

confidence: 99%

Manipulation of polystyrene nanoparticles on a silicon wafer in the peak force tapping mode in water: pH-dependent friction and adhesion force

Schiwek

Heim

Stark

et al. 2015

Journal of Applied Physics

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The friction force between nanoparticles and a silicon wafer is a crucial parameter for cleaning processes in the semiconductor industry. However, little is known about the pH-dependency of the friction forces and the shear strength at the interface. Here, we push polystyrene nanoparticles, 100 nm in diameter, with the tip of an atomic force microscope and measure the pH-dependency of the friction, adhesion, and normal forces on a silicon substrate covered with a native silicon dioxide layer. The peak force tapping mode was applied to control the vertical force on these particles. We successively increased the applied load until the particles started to move. The main advantage of this technique over single manipulation processes is the achievement of a large number of manipulation events in short time and in a straightforward manner. Geometrical considerations of the interaction forces at the tip-particle interface allowed us to calculate the friction force and shear strength from the applied normal force depending on the pH of an aqueous solution. The results clearly demonstrated that particle removal should be performed with a basic solution at pH 9 because of the low interaction forces between particle and substrate.

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AFM forces between mica and polystyrene surfaces in aqueous electrolyte solutions with and without gas bubbles

Cited by 9 publications

References 55 publications

Direct measurement of interaction forces between bovine serum albumin and poly(ethylene oxide) in water and electrolyte solutions

Direct measurement of interaction forces between bovine serum albumin and poly(ethylene oxide) in water and electrolyte solutions

Role of Air Bubbles Overlooked in the Adsorption of Perfluorooctanesulfonate on Hydrophobic Carbonaceous Adsorbents

Manipulation of polystyrene nanoparticles on a silicon wafer in the peak force tapping mode in water: pH-dependent friction and adhesion force

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