ABSTRACT
This review covers some key concepts related to embedding of the noble metal nanoparticles in polymer surfaces. The metal nanoparticles embedded into the polymer matrix can provide high-performance novel materials that find applications in modern nanotechnology. In particular, the origin of various processes that drive the embedding phenomenon, growth of the nanostructure at the surface, factors affecting the embedding including role of surface, interface energies and thermodynamic driving forces with emphasis on the fundamental and technological applications, under different conditions (annealing and ion beams) have been discussed. In addition to the conventional thermal process for embedding which includes the measure of fundamental polymer surface properties with relevant probing techniques, this review discusses the recent advances carried out in the understanding of embedding phenomenon starting from thin metal films to growth of the nanoparticles and embedded nanostructures using novel ion beam techniques.
ABSTRACT
In the present work, we report the formation of Au nanorings on quartz substrate by thermal evaporation of Au on quartz and subsequent annealing in certain conditions as a function of metal volume fraction and annealing temperature. Optical extinction cross-sections measurements and atomic force microscopy (AFM) studies have been performed on the as-deposited and annealed samples. No signature of nanoparticles formation is found in case of as-deposited samples, while spectra of annealed samples show a clear signature of surface plasmon resonance absorption (SPR) peaks around 580 nm, which reveals the formation of Au nanostructure. AFM images clearly show the formation of Au nanorings under certain conditions. The observed SPR frequency of the Au nanorings in our case is in agreement with the estimated frequency obtained from the formulation of Aizpurua et al. Optical extinction measurements at different incidence angles were performed, which showed splitting of SPR at angles beyond 20 degrees.
Subject(s)
Crystallization/methods , Gold/chemistry , Nanostructures/chemistry , Nanostructures/ultrastructure , Nanotechnology/methods , Hot Temperature , Macromolecular Substances/chemistry , Materials Testing , Molecular Conformation , Particle Size , Surface PropertiesABSTRACT
In the present work, magnetic force microscopy is employed to investigate the magnetic ordering in ion irradiated fullerene films. It is observed that magnetic domain size is approximately 100-200 nm and magnetic signal is stronger at the domain boundaries. Magnetic signal arise in irradiated films is confirmed by magnetic measurements using a superconducting quantum interference device which increases with the ion fluence. The induced magnetism is possibly due to structural defects in the amorphous carbon phase formed by ion irradiation.
Subject(s)
Crystallization/methods , Fullerenes/chemistry , Magnetics , Membranes, Artificial , Microscopy, Atomic Force/methods , Nanostructures/chemistry , Nanotechnology/methods , Electromagnetic Fields , Fullerenes/radiation effects , Heavy Ions , Macromolecular Substances/chemistry , Materials Testing , Molecular Conformation , Nanostructures/radiation effects , Nanostructures/ultrastructure , Particle Size , Surface PropertiesABSTRACT
Thin films of silica containing silver nanoparticles were deposited by magnetron co-sputtering followed by thermal annealing in air or Ar+2% H2. Laser fragmentation of the particles was carried out at two different wavelengths. The films were characterized by UV-VIS absorption spectroscopy and plasmon resonance numerical modeling based on the Mie theory, together with Rutherford backscattering elemental analysis, X-ray photoelectron spectroscopy chemical characterization, combined with statistical analysis of the transmission electron microscopy micrographs, and surface topography study by atomic force microscopy. It is demonstrated that the fragmentation is a result of a thermal process and its mechanism does not depend on the laser wavelength as long as the laser light is absorbed by the silver particles. Laser treatment with moderate fluences does not alter the precipitated metal content while fragmenting the particles. TEM study indicates that laser assisted silver particle modification can serve as a method for narrowing the particle size distribution.
