Preparation of silane-coated TiO2 nanoparticles in supercritical CO2.
J Colloid Interface Sci
; 338(2): 491-9, 2009 Oct 15.
Article
en En
| MEDLINE
| ID: mdl-19625025
ABSTRACT
Nanometric inorganic pigments are widely used as fillers for hybrid composite materials. However, these nanometric powders are hydrophilic in nature and their surface must be functionalized before use. In this work, titanium dioxide (TiO2) nanoparticles were coated using silane coupling agents with alkyl functionality. A supercritical carbon dioxide (scCO2) method was used for surface silanization. Five alkylalkoxysilanes with different alkyl chain length and structure were studied methyltrimethoxy, isobutyltriethoxy, octyltriethoxy, octyldimethylmethoxy and octadecyltrimethoxysilane. The microstructure and thermal stability of deposited monolayers were characterized using thermogravimetric analysis, ATR-IR spectroscopy, transmission electron microscopy, wettability characterization and low-temperature N2 adsorption/desorption analysis. The use of scCO2 as a solvent provided an effective approach to functionalize individual inorganic nanoparticles due to the enhanced diffusivity of the solution molecules in the aggregates interparticle voids. The trifunctional silanes employed here yielded surfaces with better thermal stabilities and greater hydrophobicities than the used monofunctional silane.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
J Colloid Interface Sci
Año:
2009
Tipo del documento:
Article
País de afiliación:
España