Characterisation and properties of nanoparticles

But we have a point of concern. What research advantage is gained in simple wet chemical methods of synthesis of nanoparticles in micro emulsions (or in greater perspective in compartmentalised conditions) gets greatly retarded in many laboratories for lack of modern infra-structural facilities, i.e. sophisticated (hence costly) physical techniques to physicochemically reveal the types of materials produced. 

The particle size in microemulsion is essentially governed by two factors [30], namely (1) the number of droplets in the preparation and (2) the inter-particle interaction associated 

The formation of nanoparticles from microemulsions need not essentially follow the template shape. Pileni [32] (as quoted by Ganguli and Ganguli) has shown that with water/isooctane/Cu( AOT)2 shapes like sphere to cylinder to mixed spherulites and cylinders to other polydisperse shapes were possible with increasing to. According to Pileni [33], the presence of salt anions can control the shape while chloride ions favour formation of nanorods, nitrate ions hinder it. The surfactant content also can have a say on the shape of nanoparticles. The infrequently observed morphologies of nanoparticles, viz. wires, trigons, hexagons, cubes etc. have so far no specific and reliable reasons for formation in micro emulsion templates. 

The nanomaterials (viz. sulphides, selenides, chromates, iodides etc.) formed in solution may exhibit absorption in ultraviolet and visible regions [7, 29]. The concentration-dependant spectra at different to values may obey Beer s law like normal absorbing solutions at concentrations not very high. The particles in nanodimensions behave like molecular solution, the molar extinction coefficient, however, depends on to or the particle size. Cu2 [ Fe(CN), ] preparations in H O/AOT/n-heptane w/o microemulsion medium at to = 5, 8, 12 and 20 have exhibited good Beer s law plots with molar extinction coefficients of 350, 365, 352 and 521 dm3 mol-1 cm-1, respectively, at 315 nm (310 nm at to = 5) 

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