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Uobičajena metoda korištena za post-sintetsku obradu nanomaterijala, žarenje, nije povoljna za obradu nanomaterijala zbog dugog trajanja procesa i velike količine utrošene energije. Stoga je bilo potrebno razviti bržu i efikasniju metodu pri kojoj neće doći do oštećenja plastičnih podloga prilikom obrade nanomaterijala. U ovom radu opisan je utjecaj intenzivne pulsirajuće svjetlosti u razvoju metalnih i ugljikovih materijala. Tehnologijom intenzivne pulsirajuće svjetlosti (Intense pulsed light, IPL) sinterirani su bakrovi i srebrovi materijali (nanočestice, nanožice, soli) i ugljikovi materijali (nanocijevi i grafen oksid) te su promatrani utjecaji IPL zračenja na morfološka i električna svojstva navedenih materijala. Srebrove i bakrove nanočestice pod utjecajem IPL-a aglomeriraju i stvaraju vodljive puteve dok IPL nanožičane vodiče čvrsto zavari za podlogu u točki kontakta. IPL obradom ugljikovih nanocjevčica povećava se vodljivost, a obradom grafenovog oksida, uz njegovu redukciju u reducirani grafen oksid (rGO) i povećanje vodljivosti, dobivene su kvalitetne anode za litij-ionske baterije i promotori paljenja plina u gorivima. IPL-om obrađeni nanomaterijali pokazali su poboljšanja u električnoj vodljivosti i stabilnosti, dok su se površinski otpor i električne otpornosti smanjile. Metoda IPL sinteriranja pokazala se kao budućnost obrade ugljikovih i metalnih nanomaterijala zbog svoje visoke iskoristivosti, jednostavnosti i kratkog vremena trajanja. The usual method used for post-synthetic processing of nanomaterials, annealing, is not favorable for processing nanomaterials due to the long duration of the process and the large amount of energy consumed. Therefore, it was necessary to develop a faster and more efficient method that will not damage plastic substrates during the processing of nanomaterials. This work describes the influence of intense pulsed light (IPL) in the development of metal and carbon based materials. Copper and silver materials (nanoparticles, nanowires, salts) and carbon materials (nanotubes and graphene oxide) were sintered with IPL technology and the effects of IPL radiation on these materials were observed. Silver and copper nanoparticles under the influence of IPL agglomerate and create conductive pathways while the nanowire conductors are firmly welded to the substrate at the point of contact. IPL treatment of carbon nanotubes increases their conductivity, and processing of graphene oxide, with its reduction to rGO and increase in conductivity, quality anodes were obtained for Lithium-ion batteries and gas ignition promoters in fuels. IPL-treated nanomaterials showed improvement in electrical conductivity and stability, while surface resistance and electrical resistivity decreased. The IPL sintering method has proven to be the future of carbon and metal nanomaterial processing due to its high efficiency, simplicity and short processing duration.

In parallel with the growing use of nanoparticle-containing products, their release into the environment over the coming years is expected to increase significantly. With many large population centers located in near-coastal areas, and increasing evidence that various nanoparticles may be toxic to a range of organisms, biota in estuarine and coastal waters may be particularly vulnerable. While size effects may be important in cases, silver nanoparticles have been found to be toxic in large part due to their release of silver ions. However, there is relatively little data available on how nanoparticle coatings can affect silver ion release in estuarine or marine waters. We have found that albumin, as a model for biocorona-forming macromolecules which nanoparticles may encounter in wastewater streams, stabilizes silver colloids from agglomeration in high salinity marine waters by electrosteric repulsion for long time periods. A minimum mass ratio of about 130 for albumin:silver nanoparticles (40 nm) was required for stable dispersion in seawater. Increasing albumin concentration was also found to reduce dissolution of nanoparticles in seawater with up to 3.3 times lower concentrations of silver ions noted. Persistent colloids and slow sustained ion release may have important consequences for biota in these environmental compartments.

U ovom pregledu prikazane su mikroemulzijske tehnike za sintezu metalnih, metal-oksidnih, sulfidnih i polimernih nanočestica. Sinteza se izvodi u mikroemulzijama voda-u-ulju, miješanjem dviju mikroemulzija, od kojih jedna sadrži kationski prekursor, a druga precipitacijski medij ili redukcijsko sredstvo. Nanočestice metala dobivaju se redukcijom metalnog kationa s jakim redukcijskim sredstvima uz oslobađanje vodika prikladnim redukcijskim sredstvom. Na sličan način mogu se pripraviti i nanočestice legura od soli različitih metala pod uvjetom da se metali međusobno miješaju. Mikroemulzijska tehnika veoma je pogodna i za nanošenje nanočestica na različite podloge. Na taj način mogu se dobiti visokoaktivni katalizatori od nanočestica Pt, Pd, Rh i drugih plemenitih metala. Metalni oksidi i hidroksidi pripravljaju se hidrolizom ili taloženjem u vodenoj jezgri mikroemulzije. Da se spriječi oksidacija nanočestica, osobito Fe, čestice se prevlače inertnim metalima, oksidima, različitim polimerima i dr. Prevlačenjem se može postići dodatna funkcionalnost; npr. prevlačenje zlatom omogućava naknadnu funkcionalizaciju organskim spojevima koji sadrže sumpor, zahvaljujući jakoj tiolnoj vezi Au–S. Polimerne prevlake smanjuju toksičnost nanočestica i povećavaju biokompatibilnost, a funkcionalne skupine na površini omogućavaju razne primjene u biomedicini. Reakcije polimerizacije ili umrežavanja mogu se inicirati u vodenim jezgrama mikroagregata kemijskim sredstvima ili npr. UV ili ionizirajućim zračenjem. Prednosti mikroemulzijske polimerizacije su velika brzina, jednolična veličina čestica, stabilnost te visoki stupanj polimerizacije. Nanočestice magnetita pobuđuju velik interes zbog primjene u biomedicini. Magnetit je biokompatibilni materijal, a može se pripremiti u obliku dobro dispergiranih nanočestica manjih od 4 nm, koje imunosni sustav ne prepoznaje. Prikazana je vlastita metoda mikroemulzijske sinteze nanočestica magnetita potpomognuta γ-zračenjem., Nanoparticles and nanomaterials have wide applications in electronics, physics, material design, being also utilized as sensors, catalysts, and more and more in biomedicine. Microemulsions are an exceptionally suitable medium for the synthesis of nanoparticles due to their thermodynamical stability, great solubility of both polar and nonpolar components, as well as their ability to control the size, dispersity and shape of the particles. This review presents microemulsion techniques for the synthesis of inorganic nanoparticles. It takes place in water-in-oil microemulsions by mixing one microemulsion with a cationic precursor, and the other with a precipitating or reducing agent, or by direct addition of reducing agents or gas (O2, NH3 ili CO2 ) into microemul sion (Fig. 1). Metal nanoparticles are used as catalysts, sensors, ferrofluids etc. They are produced by reducing the metal cation with a suitable reducing agent. In a similar way, one can prepare nanoparticles of alloys from the metal salts, provided that the metals are mutually soluble. The microemulsion technique is also suitable for depositing nanoparticles onto various surfaces. Highly active catalysts made from nanoparticles of Pt, Pd, Rh and other noble metals may be obtained in this way. Metal oxides and hydroxides may be prepared by hydrolysis or precipitation in the water core of microemulsion. Precipitation can be initiated by adding the base or precipitating agent into the microemulsion with water solution of metal ions. Similarly, nanoparticles may be prepared of sulphides, halogenides, cyanides, carbonates, sulphates and other insoluble metal salts. To prevent oxidation of nanoparticles, especially Fe, the particles are coated with inert metals, oxides, various polymers etc. Coating may provide additional functionality; e.g. coating with gold allows subsequent functionalization with organic compounds containing sulphur, due to the strong Au–S bond. Polymer coatings decrease toxicity of the nanoparticles and increase their biocompatibility, and the functional groups on the surface enable specific applications in biomedicine. Microemulsion synthesis is convenient both for organic and polymer particles. Polymerization or crosslinking reactions may be initiated in the water core of microaggregates by using chemicals, UV or ionizing radiation (Fig. 3). Microemulsion polymerization is advantageous due to fast reactions, uniform particle size, great stability and high polymerization degree. Magnetite nanoparticles induce great interest due to biomedical applications. Magnetite is a biocompatible material that may be prepared in the form of well-dispersed nanoparticles smaller than 4 nm, which are not recognized by the immune system. The authors’ own approach for the synthesis of magnetite nanoparticles using γ-irradiation assisted microemulsion technique is described (Figs. 5–10).

A three-dimensional (3D) photonic microstructure consisting of metal clusters embedded in dielectric matrix is coated with a dielectric mirror. The produced photonic structure shows optical behaviour that combines the interferential effects of the multilayer stack and the surface plasmon resonance of metal clusters. Due to its feasibility and the possibility to widely modify the optical properties of the resulting interferential-plasmonic structure, this approach represents a promising method for the production of novel optical components.

A two-step procedure for the formation of silver nanoparticles embedded in a glass matrix is studied. The procedure consists of: (i) the inclusion of silver ions in the glass matrix by electric field assisted dissolution of Ag film deposited on the glass and (ii) the aggregation of silver by thermal annealing. The optical properties of the sample, dominated by the surface plasmon resonance of metal nanoparticles in the visible spectral range, are studied by optical spectroscopy. The structural characterization is carried out by grazing-incidence small-angle X-ray scattering measurements performed at the Synchrotron Elettra (Italy) and silver depth profiles are determined using Rutherford backscattering. The results suggest that the depth profile of Ag might be tailored by modification of the parameters of metal film dissolution (electric field and temperature). Variation of thermal annealing parameters (temperature and time) allows control of the nanoparticles size. Thus, the surface plasmon absorption intensity and line shape are changed, enabling tuning of the optical properties of the sample.