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We present a method of metallic nanoparticles (mNPs) deposition from water-based colloid onto solid substrates via electrospray technique. Gold nanoparticles (AuNPs) with the size of about 13 nm were synthesized in water via chemical reduction method and characterized with UV–vis spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM). AuNPs were deposited via electrospray onto two solid substrates: silicon wafer and element of resistive memory device and characterized with scanning electron microscopy (SEM). Studies confirmed that electrospray technique can be successfully used for mNPs deposition from aqueous colloids on solid substrates without altering the substrate structure. During the electrospray process the solvent that may destroy the surface of resistive memory element evaporates and mNPs are deposited in dry conditions. The presented method is versatile and can be used for the deposition of different nanomaterials onto various types of solid substrates. [ABSTRACT FROM AUTHOR]

This paper describes the influence of the chain length and the functional group steric accessibility of thiols modifiers on the phase transfer process efficiency of water synthesized gold nanoparticles (AuNPs) to toluene. The following thiols were tested: 1-decanethiol, 1,1-dimethyldecanethiol, 1-dodecanethiol, 1-tetradecanethiol and 1-oktadecanethiol. Nanoparticles (NPs) synthesized in water were precisely characterized before the phase transfer process using Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). The optical properties of AuNPs before and after the phase transfer were studied by the UV-Vis spectroscopy. Additionally, the particle size and size distribution before and after the phase transfer of nanoparticles were investigated using Dynamic Light Scattering (DLS). It turned out that the modification of NPs surface was not effective in the case of 1,1-dimethyldecanethiol, probably because of the difficult steric accessibility of the thiol functional group to NPs surface. Consequently, the effective phase transfer of AuNPs from water to toluene did not occur. In toluene the most stable were nanoparticles modified with 1-decanethiol, 1-dodecanethiol and 1-tetradecanethiol. [ABSTRACT FROM AUTHOR]

The present paper describes a method for modification of gold (AuNPs) and silver (AgNPs) nanoparticles with n -dialkyldithiophosphates (DTP) via the phase transfer process. Two thiophosphoric acids with different chain lengths: di- n -dodecanethiophosphate (C 12 DTP) and di- n -heksadecanethiophosphate (C 16 DTP) were used as transfer agents of nanoparticles (NPs) from water to hexane. NPs synthesized by chemical reduction method in water were precisely characterized before the transfer process using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The effectiveness of phase transfer process was studied by the UV–vis spectroscopy. Nanoparticle size and size distribution before and after the process were investigated using dynamic light scattering (DLS). Phase transfer process turned out to be an effective method to obtain stable AuNPs and AgNPs modified with di- n -dodecanethiophosphate and di- n -heksadecanethiophosphate in hexane. No changes in the absorption spectra position or in NPs size and size distribution were observed after the transfer process, showing that the n -dialkyldithiophosphate-modified AuNPs and AgNPs dispersed in hexane were colloidally stable. This indicates that long hydrocarbon chains of n -dialkyldithiophosphates provide nanoparticles sufficient hydrophobicity and dispersibility in hexane. [ABSTRACT FROM AUTHOR]