These nanoparticles were created by the application of ultrasonic waves to the aqueous solutions of these salts. When the sonication was carried out in the presence of a glass microscope slide, a parylene-coated glass slide, or a silicon wafer the ionic NPs were embedded in these substrates by a one-step, ultrasound-assisted procedure. Optimization of the coating process resulted in homogeneous distributions of nanocrystals, 30 nm in size, on the surfaces of the substrates.
After 24 h of leaching into water the nanoparticles of the inorganic salts were still present on the slides, and complete leaching of nanoparticles occurred only after 96 h.
A mechanism of the ultrasound-assisted coating is proposed. The incorporation of nanocrystals into dielectric matrices, such as glass or polymers, has become a topic of broad interest in recent years. The research in the area of nanostructured composites is aimed at studying their fundamental properties as well as applications in tissue engineering, nanooptics and nanoelectronics []. Unlike the synthesis of NPs of metal oxides, metal chalcogenides, and even some metal fluorides, the synthesis of NPs of water-soluble ionic compounds has not reached the same level of attention, and only a very few publications are found [6].
This current paper describes a general method for the preparation of water-soluble ionic NPs. To help prove the formation of these NPs they were examined both in the solution in which they were formed as well as in solid matrices. They were embedded in the solid substrate by the sonochemical method, which was performed subsequently to their formation. Various methods have been used for the incorporation and growth of arrays of nanocrystals on or embedded into substrate hosts.
One of these methods is chemical bonding. For example, the cross-linking process was used for the embedding of NaCl nanocrystals into polymers containing unsaturated double bonds [1,2]. Some other methods were developed for the coating of polymers with nanocrystals of NaCl, Na 2 CO 3 and Na 2 SO 4 , exploiting the difference in wettability between the regions of the patterned polymeric substrate [3].
