TITLE:
Click Reaction Functionalization of Hydroxylated Nanoparticles by Cyclic Azasilanes for Colloidal Stability in Oilfield Applications
AUTHORS:
Radhika Suresh, Sankaran Murugesan, Valery Khabashesku
KEYWORDS:
Functionalization, Azasilane, Nanoparticles, Colloidal Stability, Oilfield Applications
JOURNAL NAME:
Advances in Nanoparticles,
Vol.10 No.1,
February
26,
2021
ABSTRACT: The growing interest in functionalized nanoparticles
and their implementation in oilfield applications
(e.g., drilling fluids and enhanced oil recovery (EOR)) facilitate the ongoing efforts to improve their chemical
functionalization performance in stabilization of water based or hydrocarbon
based nanofluids. Cyclic azasilanes (CAS), substituted
1-aza-2-silacyclopentanes, possess a strained 5-member ring structure. Adjacent
Si and N atoms in the ring provide opportunity for highly efficient covalent
surface functionalization of hydroxylated nanoparticles through a catalyst-free
and byproduct-free click reaction. In this
work, hydroxylated silica, alumina, diamond, and carbon coated iron
core-shell nanoparticles have been studied for monolayer CAS functionalization. Two cyclic azasilanes with
different R groups at N atom, such as methyl (CAS-1) and aminoethyl
(CAS-2), have been utilized to functionalize
nanoparticles. All reactions were found to readily proceed under mild
conditions (room temperature, ambient pressure) during 1 - 2 hours of
sonication. CAS functionalized adducts of hydroxylated nanoparticles have been
isolated and their microstructure, composition, solubility and thermal stability have
been characterized. As a result, it has been demonstrated, for the first time,
that covalent surface modification with cyclic azasilanes can be extended
beyond the previously known porous silicon structures to hydroxylated silica,
alumina and carbon nanoparticles. The developed methodology was also shown to
provide access to the nanoparticles with the hydrophilic or hydrophobic surface
functional groups needed to enable oilfield applications (e.g., EOR, tracers,
drilling fluids) that require stable water based or hydrocarbon based colloidal
systems.