Effects of polymers and surfactants on the stability of oil droplets, an AFM study
This paper investigates the interplay among oil droplets in aqueous media by utilizing atomic force microscopy ( AFM) and explores the impacts of the polymer poly ( sodium 4-styrenesulfonate) ( PSS) and the anionic surfactant sodium dodecyl sulfate ( SDS) on the stability of oil droplets.Furthermore, the interaction between PSS and SDS in aqueous environments is simulated by employing molecular dynamics simulation software.Our findings reveal oil droplets tend to readily coalesce in salt solutions devoid of polymer and surfactant.Upon the addition of 100 mg/L PSS to the aqueous solution, the oil droplets exhibit enhanced stability, primarily attributed to the steric hindrance imparted by the adsorption layer of PSS.This layer effectively impedes the coalescence of oil droplets.However, the coexistence of 100 mg/L PSS and 0.1 mM/L SDS induces the re-coalescence of oil droplets.This phenomenon primarily arises from the propensity of PSS and SDS to form clusters when present concurrently.At this juncture, only a fraction of PSS is absorbed at the interface, rendering ineffective steric hindrance.Consequently, oil droplets coalesce when in close proximity, thereby compromising the stability of the oil-in-water system.
atomic force microscopepolymerssurfactantswaste wateroil dropletsmolecular simulation
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