J Colloid Interface Sci
November 2007
The simple recrystallization process is innovatively used to obtain the nanoparticles of copper phthalocyanine by a simple method. Liquid-liquid interface recrystallization technique (LLIRCT) has been employed successfully to produce small sized copper phthalocyanine nanoparticles with diameter between 3-5 nm. The TEM-SAED studies revealed the formation of 3-5 nm sized with beta-phase dominated mixture of alpha and beta copper phthalocyanine nanoparticles.
View Article and Find Full Text PDFWe demonstrate the phase transfer of silver nanoparticles synthesized in an aqueous medium into hexane containing the cationic surfactant octadecylamine (ODA). During vigorous shaking of the biphasic mixture, rapid phase transfer of the silver nanoparticles into the organic phase was observed. The phase transfer of the silver nanoparticles arises due to coupling of the silver nanoparticles with the ODA molecules present in organic phase via either coordination bond formation or weak covalent interaction.
View Article and Find Full Text PDFWe demonstrate that the amino acid tyrosine is an excellent reducing agent under alkaline conditions and may be used to reduce Ag+ ions to synthesize stable silver nanoparticles in water. The tyrosine-reduced silver nanoparticles may be separated out as a powder that is readily redispersible in water. The silver ion reduction at high pH occurs due to ionization of the phenolic group in tyrosine that is then capable of reducing Ag+ ions and is in turn converted to a semi-quinone structure.
View Article and Find Full Text PDFThis work describes the formation of interlinked gold and silver nanoclusters at controlled pH using 4-aminothiophenol (ATP) as a molecular interconnect. UV-visible spectra give on intercrystal plasmon resonance band in the region 550-580 nm. The crystalline heteroassembly formation is also evident from the transmission electron microscopic (TEM) images, whereas X-ray photoelectron spectroscopic (XPS) analysis of the aggregates shows the presence of charged -N species, indicating electrostatic interaction of -N with Ag nanoclusters.
View Article and Find Full Text PDFThe one-step electrostatic complexation, reduction of aqueous chloroplatinate ions, and capping of the platinum nanoparticles thus formed by hexadecylaniline Langmuir monolayers is described. The capping of the platinum nanoparticles formed spontaneously at the air-water interface by hexadecylaniline enables their facile transfer as multilayers onto suitable solid substrates by the Langmuir-Blodgett technique. The real-time reduction of the aqueous chloroplatinate ions at the air-water interface was followed by measurement of the pressure-area isotherms, while the multilayer Langmuir-Blodgett films were characterized by quartz crystal microgravimetry, transmission electron microscopy, electron diffraction, and X-ray photoemission spectroscopy.
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