Open AccessTitanium dioxide/silver nanoparticle bilayers prepared in self-assembly processes
Author(s) -
Julia Maciejewska,
Magdalena Oćwieja,
Zbǐgniew Adamczyk,
Elżbieta Bielańska,
Bogna D. Napruszewska
Publication year - 2016
Publication title -
annales universitatis mariae curie-skłodowska. sectio aa, chemia
Language(s) - English
Resource type - Journals
eISSN - 2083-358X
pISSN - 0137-6853
DOI - 10.17951/aa.2016.71.1.29
Subject(s) - silver nanoparticle , nanoparticle , zeta potential , titanium dioxide , isoelectric point , materials science , chemical engineering , ionic strength , nanotechnology , colloid , ionic bonding , chemistry , aqueous solution , composite material , organic chemistry , ion , engineering , enzyme
A new method for the preparation of TiO 2 /Ag bilayers via colloid self-assembly process using well-characterized titanium dioxide and silver suspensions was developed. The titanium dioxide nanoparticles, forming a supporting layer, were 46 nm in diameter, exhibiting an isoelectric point at pH 6.4. The silver nanoparticles, forming an external layer of the diameter of 50 nm were prepared via a chemical reduction method with the presence inorganic phosphate salts. The electrophoretic mobility measurements revealed that the zeta potential of silver nanoparticles was highly negative for a broad range of pH and ionic strengths. By explaining this information, the optimum condition for the silver nanoparticle immobilization on TiO 2 supporting layers were selected. The coverage of the first layer was adjusted by ionic strength of the suspensions and by the deposition time. Afterward, the silver nanoparticle monolayers of controlled coverage were deposited under the diffusion-controlled transport. Their coverage was determined by a direct enumeration of deposited nanoparticles from AFM images and SEM micrographs. The experimental results showed that for extended deposition times, the coverage of silver nanoparticle layers significantly increases with ionic strength. Therefore, it was proven that the formation of bilayers is mainly controlled by electrostatic interactions and that it is feasible to produce uniform TiO 2 /Ag materials of desired coverage and structure.