2,266 research outputs found
Synthesis of Al and Ag nanoparticles through ultra-sonic dissociation of thermal evaporation deposited thin films for promising clinical applications as polymer nanocomposite
Nanoparticles (NPs) having well-defined shape, size and clean surface serve as ideal model system to investigate surface/interfacial reactions. Ag and Al NPs are receiving great interest due to their wide applications in bio-medical field, aerospace and space technology as combustible additives in propellants and hydrogen generation. Hence, in this study, we have synthesized Ag and Al NPs using an innovative approach of ultra-sonic dissociation of thin films. Phase and particle size distributions of the Ag and Al NPs have been determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thin film dissociation/dissolution mechanism, hence conversion into NPs has been characterized by SEM- scanning electron microscope. EDXA & ICPMS have been performed for chemical analysis of NPs. Optical properties have been characterized by UV-Vis and PL spectroscopy. These NPs have also been investigated for their anti-bacterial activity against Escherichia coli bacteria. To the best of our knowledge, this is the first time when NPs has been synthesized by ultra-sonic dissociation of thin films. As an application, these NPs were used further for synthesis of nanocomposite polymer membranes, which show excellent activity against bio film formation
Growing Surface Tension of Amorphous-Amorphous Interfaces on Approaching the Colloidal Glass Transition
There is mounting evidence indicating that relaxation dynamics in liquids
approaching their glass transition not only becomes increasingly cooperative
(1,2) but the relaxing regions also become more compact in shape(3-7). While
the surface tension of the interface separating neighboring relaxing regions is
thought to play a crucial role in deciding both their size and
morphology(8-10), owing to the amorphous nature of these regions, even
identifying these interfaces has not been possible in bulk liquids. Here, by
devising a scheme to identify self-induced disorder sites in bulk colloidal
liquids, we directly quantified the dynamics of interfaces delineating regions
of high and low configurational overlap. This procedure also helped unveil a
non-monotonicity in dynamical correlations that has never been observed in bulk
supercooled liquids. Using the capillary fluctuation method (11,12), we
measured the surface tension of amorphous-amorphous interfaces with
supercooling and find that it increases rapidly across the mode-coupling area
fraction. Remarkably, a similar growth in the surface tension is also seen in
the presence of a pinned amorphous wall. Our observations help prune theories
of glass formation and opens up new research avenues aimed at tuning the
properties of amorphous-amorphous interfaces, and hence the glass itself, in a
manner analogous to grain boundary engineering in polycrystals (13)
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