Creation of a functional polysiloxane layer on the surface of magnetic nanoparticles using the sol-gel method

Abstract

The developed methods using tetraethoxysilane and trifunctional silanes were applied to obtain Fe 3 O 4 magnetic particles that contain amino groups with compositions of ≡Si(CH 2 ) 3 NH 2 , ≡Si(CH 2 ) 3 NH(CH 2 ) 2 NH 2 , and [≡Si(CH 2 ) 3 ] 2 NH. The XRD data show that the nuclei of nanoparticles in the obtained materials preserve the structure of the primary carrier, namely, that of Fe 3 O 4 magnetite. The ther mograms show a high thermal stability of the applied surface layers, i.e., their destruction was found to start at temperature above 250°C. The DRIFT spectra indicate the formation of the silica bond framework in the surface layers of nanoparticles and also the existence of hydrogen bonds between amino groups and silanol groups with the participation of water molecules aided. All of the obtained materials exhibit magnetic prop erties and offer promising application in medicine.

Magneto-Sensitive Adsorbents Modified by Functional Nitrogen-Containing Groups

“…The results obtained by acid-base titrations are very close to those published previously [10, 11]. The small differences in the content of amino group values could be attributed by the nature of sol-gel procedure, in which a number of synthesis factors can influence on the properties of the final material.…”

“…In the Table 1, values of specific surface area ( S sp ) are presented. As before, the values of S sp are very similar, when compared with the previous results [10, 11]. Small deviations in the values of S sp may be caused by measurement error or small differences in the structure of materials, obtained by sol-gel method.…”

“…Five different magnetic amino-functionalized silica-based materials were synthesized and tested as potential adsorbents for copper(II) ions. Each of examined adsorbents was synthesized on the basis of sol-gel procedure, which is detailed described in papers [10, 11]. In order to compare sorption measurements, three different monomers containing different number and structure of amino groups were used to modify surface of magnetic silica materials (Table 1).…”

“…Each of examined amino-functionalized silica adsorbents with magnetic core was synthesized on the basis of sol-gel procedure, which is detailed described in papers [10, 11]. The magnetite nanoparticles were obtained by co-precipitation of iron(II) and (III) salts in a basic medium, reported by [12].…”

“…In the literature, many variety of methods, describing coating Fe 3 O 4 nanoparticles, can be found, e.g., direct modification of magnetite by amino-containing silanes [5, 7] and magnetite coated with polysiloxane layer and their further modification by amino containing silane [3, 4, 8, 9] as well as one-step technique using tetraethoxysilane and N-containing silanes [10, 11]. The first method does not allow to obtain tight and continuous layer covered magnetite nanoparticles.…”