Smoothly Tunable Surface Properties of Aluminum Oxide Core–Shell Nanoparticles By A Mixed-Ligand Approach

Abstract

We present a facile solution-based procedure for tailoring the surface properties of aluminum oxide nanoparticles (AlOx-NPs) by the formation of tunable core-shell systems with self-assembled monolayers. By employing chained molecules with a phosphonic acid anchor group and either hydrophobic or hydrophilic chains the surface properties of the nanoparticles change dramatically. So, the solubility can be tuned orthogonal from trifluorotoluene (CF3-C6H5) for hydrophobic shell to water (H2O) for hydrophilic functionalization respectively. Spray coated films of those functionalized nanoparticles exhibited superhydrophobic or superhydrophilic properties. The surface properties can be tuned smoothly by the formation of a mixed ligand monolayer from corresponding stoichiometric mixtures of the ligands. The core-shell nanoparticles were investigated by means of thermogravimetric analysis, TGA; Fourier transform infrared spectroscopy, FTIR; and static contact angle goniometry, SCA. The effect of different dipole moments of the SAM molecules in mixed shell nanoparticles to their stability in dispersions was studied by zeta potential measurements.

Advanced microemulsion synthesis and characterization of wollastonite (CaSiO3)/polystyrene one-dimensional nanorods with core–shell structures

“…10(c)). As expected, the hydrophobicity of the CSNRs SDS /PP film is higher than that of CSNRs CTAB /PP owing to the high level of grafting, the dispersibility and stability of the nanorods, and the large number of hydrophobic groups present as the polymer shell is grafted on the surface of the hydrophilic core (Portilla & Halik, 2014;Sharma et al, 2012). The reduced contact angle of the CSNRs CTAB/SDS /PP nanocomposites compared with that of pristine PP is owing to the relative absence of ungrafted WNRs present in the PP matrices.…”

Tuning the reactivity of Al/Fe2O3 nanoenergetic materials via an approach combining soft template self-assembly with sol–gel process process

“…Under standard atmospheric conditions, the Al 2 O 3 shell can become partially hydroxylated, providing an additional route for surface functionalization [21,22]. Ample literature is available about the chemical functionalization of Al 2 O 3 oxide on bulk Al particles using the condensation of carboxylic acids to surface bound hydroxyls in order to form self-assembled monolayers (SAMs) [22][23][24][25]. As shown in Fig.…”

Region‐Selective Deposition of Core–Shell Nanoparticles for 3 D Hierarchical Assemblies by the Huisgen 1,3‐Dipolar Cycloaddition

“…Thec ore-shell NPs required for step bw ere fabricated by at echnique previously reported by our group. [19] Themethod enables easy access to azide-and alkyne-terminated NPs by choosing corresponding PA molecules 2 or 3,r espectively.A lkyne terminated PA 3 was grafted onto the AlO x core,l eading to NPs 4.T hese NPs undergo the CuAACw ith the azide headgroup of PA 2 on substrate ii (step b, Figure 1; Scheme 1). Ther esult is the region-selectively deposited layer of NPs 4 on substrate ii to give iii.The second layer used indium tin oxide (ITO) NPs 5 that had been functionalized with azide terminated PA 2,that is,the reactive counterpart of NP 4.Asaresult, deposition of NPs 5 subsequently resulted in ac lick reaction with the unreacted alkyne groups of 4 from the first NP layer of substrate iii (step c, Figure 1).…”

“…Theo btained substrate v features ad efined ternary layered stack of selectively deposited core-shell NPs with three different cores (AlO x ,I TO,a nd CeO 2 ). Ther espective cores were chosen because they represent typical model systems (AlO x [19,20] ), high-performance materials (ITO [21] ), or are promising candidates for various possible applications ranging from catalysis and optics,t oe lectronics (CeO 2 [22] ). To establish the successful CuAACunder the applied conditions, the decrease of the azide band in the infrared was monitored by FTIR spectroscopy of dried NP powder (Supporting Information).…”

“…To establish the successful CuAACunder the applied conditions, the decrease of the azide band in the infrared was monitored by FTIR spectroscopy of dried NP powder (Supporting Information). [9,10,19] Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used to characterize the functionalized substrates.F igure 2a-c present the AFM scans of substrates iii-v and ac omparison of the corresponding height profiles (Figure 2d). Them ean diameter of the particles 4 (55 nm AE 19 nm), 5 (56 nm AE 16 nm), and 6 (66 nm AE 20 nm) was determined by dynamic light scattering (DLS,s ee the Supporting Information).…”