Skip to Main content Skip to Navigation
Journal articles

Hydrophobization of Silica Nanoparticles in Water: Nanostructure and Response to Drying Stress

Abstract : We report on the impact of surface hydrophobization on the structure of aqueous silica dispersions and how this structure resists drying stress. Hydrophilic silica particles were hydrophobized directly in water using a range of organosilane precursors, with a precise control of the grafting density. The resulting nanostructure was precisely analyzed by a combination of small-angle X-ray scattering (SAXS) and cryo-microscopy (cryo-TEM). Then, the dispersion was progressively concentrated by drying, and the evolution of the nanostructures as a function of the grafting density was followed by SAXS. At the fundamental level, because the hydrophobic character of the silica surfaces could be varied continuously through a precise control of the grafting density, we were able to observe how the hydrophobic interactions change particles interactions and aggregates structures. Practically, this opened a new route to tailor the final structure, the residual porosity, and the damp-proof properties of the fully dried silica. For example, regardless of the nature of the hydrophobic precursor, a grafting density of 1 grafter per nm2 optimized the interparticle interactions in solution in view to maximize the residual porosity in the dried material (0.9 cm3/g) and reduced the water uptake to less than 4% in weight compared to the typical value of 13% for hydrophilic particles (at T = 25 °C and relative humidity = 80%).
Document type :
Journal articles
Complete list of metadatas

Cited literature [12 references]  Display  Hide  Download

https://hal.sorbonne-universite.fr/hal-01520275
Contributor : Gestionnaire Hal-Upmc <>
Submitted on : Wednesday, May 10, 2017 - 11:24:05 AM
Last modification on : Tuesday, October 6, 2020 - 2:58:02 PM
Long-term archiving on: : Friday, August 11, 2017 - 12:53:47 PM

File

Moro_2017_Hydrophobization_of....
Files produced by the author(s)

Identifiers

Citation

Solenn Moro, Caroline Parneix, Bernard Cabane, Nicolas Sanson, Jean-Baptiste d'Espinose de Lacaillerie. Hydrophobization of Silica Nanoparticles in Water: Nanostructure and Response to Drying Stress. Langmuir, American Chemical Society, 2017, 33 (19), pp.4709-4719. ⟨10.1021/acs.langmuir.6b04505⟩. ⟨hal-01520275⟩

Share

Metrics

Record views

402

Files downloads

401