Predicting and measuring repulsive van der Waals forces for a Teflon AF™–solvent–α-alumina system

Bohling, Christian; Sigmund, Wolfgang M.

doi:10.1016/j.colsurfa.2014.08.018

Cited by 7 publications

(3 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Results and Discussionsupporting

confidence: 89%

“…The calculated ΔG LW between gypsum and −CF 3 was positive, albeit small, indicating a weak repulsive vdW force at 0.165 nm separation. Similar repulsive vdW interactions were also reported by Bohling et al 64 In water, ΔG AB accounts for the hydrophobic attraction (negative value) or the hydrophilic repulsion (positive value) between materials due to the cohesion of water molecules. 55 Both gypsum and −OH SAM are electrodonor monopolar materials (Table S3) that interact strongly with water molecules, which leads to repulsion between them.…”

Section: Resultssupporting

confidence: 79%

See 1 more Smart Citation

Predominant Effect of Material Surface Hydrophobicity on Gypsum Scale Formation

Huang

Zuo

et al. 2020

Environ. Sci. Technol.

View full text Add to dashboard Cite

Scale formation is an important challenge in water and wastewater treatment systems. However, due to the complex nature of membrane surfaces, the effects of specific membrane surface characteristics on scale formation are poorly understood. In this study, the independent effect of surface hydrophobicity on gypsum (CaSO 4 •2H 2 O) scale formation via surface-induced nucleation and bulk homogeneous nucleation was investigated using quartz crystal microbalance with dissipation (QCM-D) on self-assembled monolayers (SAMs) terminated with −OH, −CH 3 , and −CF 3 functional groups. Results show that higher surface hydrophobicity enhances both surface-induced nucleation of gypsum and attachment of gypsum crystals formed from homogeneous nucleation in the bulk solution. The enhanced surface-induced nucleation is attributed to the lower nucleation energy barrier on a hydrophobic surface, while the increased gypsum crystal attachment results from the favorable hydrophobic interactions between gypsum and more hydrophobic surfaces. Contrary to previous findings, the role of Ca 2+ adsorption in surface-induced nucleation was found to be relatively small and similar on the different SAMs. Therefore, increasing material hydrophilicity is a potential approach to reduce gypsum scaling.

show abstract

Section: Results and Discussionsupporting

confidence: 89%

Section: Resultssupporting

confidence: 79%

Predominant Effect of Material Surface Hydrophobicity on Gypsum Scale Formation

Huang

Zuo

et al. 2020

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…When the condition ε 1 ≤ ε 2 ≤ ε 3 or ε 1 ≥ ε 2 ≥ ε 3 is met, in other words, when the dielectric response fucntion (DRF) of the intervening medium lies between those of the other two phases, the preceding equations give a negative Hamaker constant, indicating repulsion of the contacting material from the surface. Repulsive vdW forces are responsible for several natural phenomena, including the climbing of liquid helium up the walls of containers and the spreading of alkanes across the surface of water. , The majority of documented repulsive vdW interactions have been measured using the colloid probe technique for atomic force microscopy to measure forces between a particle and surface through a liquid-intervening medium. − …”

Section: Theorymentioning

confidence: 99%

Repulsive van der Waals Forces Self-Limit Native Oxide Growth

Bohling

Sigmund

2015

Langmuir

View full text Add to dashboard Cite

Silicon is one of the most studied materials, yet questions remain unanswered about its unusual property of growing a self-limiting native oxide that attains its final thickness in a matter of hours yet months later has not grown further. For the first time, we have explored this self-limiting growth in terms of repulsive van der Waals (vdW) forces generated by the combination of material properties inherent to the system. These repulsive forces represent an energy barrier preventing additional oxidizing chemicals, mainly oxygen and water, from adsorbing on the surface as well as hindering diffusion of those that do adsorb toward the interface. We have also proven that this native oxide can be increased in thickness at room temperature and without reactive species by changing the oxidation environment to one predicted by theory to result in attractive vdW forces, thus allowing oxygen/water to interact with the surface more freely.

show abstract

van derWaalsForces

2018

Surface and Interfacial Forces 2e

View full text Add to dashboard Cite

Predicting and measuring repulsive van der Waals forces for a Teflon AF™–solvent–α-alumina system

Cited by 7 publications

References 25 publications

Predominant Effect of Material Surface Hydrophobicity on Gypsum Scale Formation

Predominant Effect of Material Surface Hydrophobicity on Gypsum Scale Formation

Repulsive van der Waals Forces Self-Limit Native Oxide Growth

van derWaalsForces

Contact Info

Product

Resources

About