Facile surface tailoring of metal oxide nanoparticles via a two-step modification approach

Abstract

The tailoring of surface properties of metal oxide nanoparticles is highly important to exploit their benefits in an optimal way for diverse applications. For example, in polymer matrix nanocomposites one of the most critical aspects is the interaction of the particles with the matrix, which is determined by the chemistry of the particle surface and can be adjusted by attachment of organic ligands. Whilst many empirical solutions have been presented for specific combinations of particles and matrix, generalized approaches are not available yet. As a versatile and arbitrary method to permanently modify the surface of metal oxide nanoparticles, we present a two-step approach and prove its applicability for the versatile adjustment of surface properties of two types of nanoparticles.

Mechanistic Aspects in the Formation, Growth and Surface Functionalization of Metal Oxide Nanoparticles in Organic Solvents

“…For example, polymerizable vinyl‐group containing ligands were used to functionalize zirconia nanoparticles for their incorporation into polymers like poly(methyl methacrylate or polyurethane . A two‐step modification approach involving silane chemistry was used to functionalize zirconia and alumina nanocrystals with carboxylic acids with a broad range of terminal functionalities . Agglomerated indium tin oxide (ITO) nanoparticles, obtained by the benzyl alcohol route, were transformed into long‐term stable dispersions in chloroform (CHCl 3 ) by stabilizing them by weakly coordinating ligands like primary unbranched alkylamines with different chain lengths .…”

“…[271] At wo-step modification approach involving silane chemistry was used to functionalize zirconia and alumina nanocrystals with carboxylic acids with ab road range of terminal functionalities. [272] Agglomerated indium tin oxide (ITO) nanoparticles, obtained by the benzyl alcohol route, were transformed into long-term stable dispersions in chloroform (CHCl 3 )b ys tabilizingt hem by weakly coordinating ligandsl ike primary unbrancheda lkylaminesw ith different chain lengths. [273] In another study,acomparison of the postsynthetic stabilization of ITO and ZrO 2 nanoparticles with weakly ands trongly coordinating ligands showedt hat for the ITO nanoparticles the weak and unspecific coordination of n-alkylamines led to stable nanoparticle dispersions in CHCl 3 (Figure 10, left), while the stabilization of ZrO 2 nanoparticles in the same solvent was achieved by addition of fatty acids through the selectiveb inding of the carboxylate groups on the particles urface (Figure 10, right).…”

Verbesserung von Kunstharzbeschichtungen durch Nanopartikel mit maßgeschneiderter Oberflächenmodifizierung

“…Basierend auf der Bildung von Amidbindungen wurden Carbonsäuren mit den an den Nanopartikeln verankerten Aminogruppen (des angebundenen APTES) zur Reaktion gebracht, wobei DIC als Aktivator fungierte. Durch die Wahl der entsprechenden Carbonsäure konnte so eine variable Einstellung der partikulären Oberflächeneigenschaften erreicht werden [24]. Hierfür wurden die Partikel durch Rühren in Ethanol dispergiert und die entsprechende Modifizierungslösung zugegeben, welche aus der Carbonsäure sowie DIC in Ethanol bestand.…”

Enhancement of the Mechanical Properties of Nanoparticulate Thin Coatings via Surface Modification and Cross‐Linking Additive

“…The latter has the function of a cross-linking agent to form the network between the particle aggregates. The concentration of the bound modification ligand, which was 6.9 wt % of modification ligand per gram of particles, was determined by gravimetric analysis using a thermogravimetric analyzer (Mettler Toledo TGA/DSC, under oxygen flow in the range of 25-700°C) and compared to the research of Kockmann et al [22]. For characterization of the suspension stability after adding the cross-linking additive, the formulations were measured by transmission and backscattering (Turbiscan, Formulaction) as it is described in [23][24][25].…”

“…To modify the particles in small aggregate sizes, they were suspended in ethanol using a solids concentration of 10 wt % and stabilized electrostatically (pH* = 5, similar to [7]) with nitric acid to disperse them in a planetary ball mill (PM400, Retsch) for 2 h at 250 rpm using yttrium-stabilized zirconium oxide beads (SiLibeads, Sigmund Lindner GmbH, d GM = 200 mm) and a filling ratio of 30 %. At the end of this predispersing step, the particles were modified with the ligand APTES (99 %, Aldrich) as described by Kockmann et al [22]. After washing the particles with technical ethanol and hexane, they were dispersed by ultrasonication for approximately 1 min.…”