Carboxylation and Decarboxylation of Aluminum Oxide Nanoparticles Using Bifunctional Carboxylic Acids and Octylamine

Abstract

The carboxylation of alumina nanoparticles (NPs), with bifunctional carboxylic acids, provides molecular anchors that are used for building more complexed structures via either physisorption or chemisorption. Colloidal suspensions of the NPs may be prepared by covalently bonding a series of carboxylic acids with secondary functional groups (HO2C-R-X) to the surface of the NPs: lysine (X = NH2),p-hydroxybenzoic acid (X = OH), fumaric acid (X = CO2H), and 4-formylbenzoic acid (X = C(O)H). Subsequent reaction with octylamine at either 25°C or 70°C was investigated. Fourier transform IR-attenuated reflectance spectroscopy (FTIR-ATR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) along with energy dispersive X-ray (EDX) analysis were used to characterize the bifunctionalized monolayers and/or multilayer corona surrounding the alumina NPs and investigate the reaction mechanism of octylamine with the functional groups (X) of the NPs. Except for the fumaric functionalized NPs, addition of octylamine to the functionalized NPs leads to removal of excess carboxylic acid corona from the surface via an amide formation. The extent of the multilayer is dependent on the strength of the acid⋯acid interaction.

Synergistic toughening of nanocomposite hydrogel based on ultrasmall aluminum hydroxide nanoparticles and hydroxyapatite nanoparticles

“…In the case of HAp NPs, the diffraction angles are 25.99, 29.10, 31.84, 39.94, and 46.61°, the d spacing are 3.43, 3.06, 2.80, 2.25, and 1.94 Å, respectively. All diffraction peaks of both Al(OH) 3 NPs and HAp NPs are consistent with other reports .…”

The mechanism underlying the functionalisation of cobalt nanoparticles by carboxylic acids: a first-principles computational study

“…In light of the proposed acid-functionalisation mechanism, follow-up experimental preparation and analysis via infrared (IR) and X-ray photoelectron spectroscopy (XPS), and evaluation of zeta potentials, could be employed to capture the effective surface charge and Co:C atomic ratio of functionalised NPs for a more accurate estimation of the carboxylic acid saturation rate, binding conformation, and packing density. [76][77][78] Changing the ionic strength of the medium might be a good strategy to obtain higher coating densities within the collapsedsite defects on the NP surface, as demonstrated on the example of Au NPs. 79 The observed behaviour, together with the comprehension that such organic coatings are often synthesised with the loss of hydrogen, indicates that the path of hydrogen should also be investigated.…”

Biotechnological Application of Surface Modified Cerium Oxide Nanoparticles

“…Besides, they have been used in solid oxide fuel cells, for glass-polishing and as an ultraviolet absorbent (Das et al, 2013;Ge et al, 2015).The biotechnological importance of glutaraldehyde as an activator/stabilizer/ surface modification ligand/crosslinking agent for the immobilization of β-galactosidase on a plethora of immobilization matrices has been excellently reviewed rather recently (Johnson et al, 2011;Satar et al, 2017). Moreover, the modification of matrices via carboxylation prior to enzyme immobilization ensures anchoring of the enzyme molecules to the matrices efficiently and in greater amount with improved stability either by physisorption or chemisorption (Ansari et al, 2015;Alexander et al, 2016).…”