Hydrophobic Interactions Increase Attachment of Gum Arabic- and PVP-Coated Ag Nanoparticles to Hydrophobic Surfaces

Abstract

A fundamental understanding of attachment of surface-coated nanoparticles (NPs) is essential to predict the distribution and potential risks of NPs in the environment. Column deposition studies were used to examine the effect of surface-coating hydrophobicity on NP attachment to collector surfaces in mixtures with varying ratios of octadecylichlorosilane (OTS)-coated (hydrophobic) glass beads and clean silica (hydrophilic) glass beads. Silver nanoparticles (AgNPs) coated with organic coatings of varying hydrophobicity, including citrate, polyvinylpyrrolidone (PVP), and gum arabic (GA), were used. The attachment efficiencies of GA and PVP AgNPs increased by 2- and 4-fold, respectively, for OTS-coated glass beads compared to clean glass beads. Citrate AgNPs showed no substantial change in attachment efficiency for hydrophobic compared to hydrophilic surfaces. The attachment efficiency of PVP-, GA-, and citrate-coated AgNPs to hydrophobic collector surfaces correlated with the relative hydrophobicity of the coatings. The differences in the observed attachment efficiencies among AgNPs could not be explained by classical DLVO, suggesting that hydrophobic interactions between AgNPs and OTS-coated glass beads were responsible for the increase in attachment of surface-coated AgNPs with greater hydrophobicity. This study indicates that the overall attachment efficiency of AgNPs will be influenced by the hydrophobicity of the NP coating and the fraction of hydrophobic surfaces in the environment.

Bioavailability of silver nanoparticles and ions: from a chemical and biochemical perspective

“…This, in turn, may then affect deposit feeders and other benthic organisms. Stable Ag NP suspensions, as produced in the laboratory, are stabilized by using various surface coatings, as described in §2, which confer stability by building up an electrical charge at the surfaces of Ag NPs, or by steric stabilization [50]. The surface charge of Ag NPs is most often negative at neutral pH, if weak acids are used as coatings and is strongly pH-dependent.…”

Simple Analysis for Interaction between Nanoparticles and Dye-Containing Vesicles as a Biomimetic Cell-Membrane

“…The layer thickness (t) of DMPG (lipid bilayer) and PVP-AgNPs (PVP coating) was cited in reported data. 17 In contrast, the d value was smaller than that of vesicles, because x-AgNPs are small (ca. 4-7 nm).…”

“…9 mL of 0.1 M silver nitrate was added to 280 mL of 5.36 g/L aqueous PVP suspension while stirring. 17 After stirring for 5 min, 11 mL of 0.08 M sodium borohydride was then added to the solution and stirred for 10 min. The PVP-AgNPs were ultracentrifuged at 14,000 rpm, then re-suspended in water.…”

Simple Analysis for Interaction between Nanoparticles and Fluorescence Vesicle as a Biomimetic Cell for Toxicological Studies

“…PVP-AgNPs was prepared by the seed-mediated method. 16 9 mL of 0.1 M silver nitrate was added to 280 mL of 5.36 g/L aqueous PVP suspension while stirring. After stirring for 5 min, 11 mL of 0.08 M sodium borohydride was then added to the solution, and stirred for 10 min.…”