Self-assembled monolayers of alkanesulfonic and -phosphonic acids on amorphous iron oxide nanoparticles

C. Yee, G. Kataby, Abraham Ulman, T. Prozorov, H. White, A. King, M. Rafailovich, J. Sokolov, A. Gedanken

Research output: Contribution to journalArticle

Abstract

We have functionalized amorphous Fe2U3 nanoparticles with alkanesulfonic and octadecanephosphonic acids. TEM reveals nanoparticles 5-10 nm in diameter. FTIR spectra suggest that while in all cases the alkyl chains are packed in a solid-like arrangement, packing disorder increased with decreasing chain length. TGA of the sulfonic acid-functionalized Fe 2O 3 nanoparticles shows that moieties started to decompose and desorb from the iron oxide surface at about 260°C. In the case of the octadecanephosphonic acid (OPA)-functionalized Fe 2O 3, moieties started to decompose and desorb at 340°C. It is suggested that free Fe-OH groups can serve as proton donors to assist in the sulfonic acid desorption process and that because of the diprotic nature of the phosphonic acid these free surface Fe-OH groups may no longer be available. Among all, the octadecanesulfonic acid coating displays the lowest magnetization, which may be explained by the high packing and ordering of the alkyl chains on the particle surface. The saturation curve of the OPA case gives the smallest value of magnetization we have ever measured for functionalized Fe 2O 3 nanoparticles. It is suggested that the spin state of surface Fe 3+ ions is affected by the bonded surfactant, through a mechanism of pπ-dπ P-O, and dπ-dπ Fe-P interactions and that the phosphonate empty d orbitals increase magnetic interactions between neighboring Fe 3+ spins.

Original languageEnglish (US)
Pages (from-to)7111-7115
Number of pages5
JournalLangmuir
Volume15
Issue number21
StatePublished - Oct 12 1999

Fingerprint

Phosphorous Acids
Self assembled monolayers
Iron oxides
iron oxides
Nanoparticles
nanoparticles
acids
Sulfonic Acids
Acids
Alkanesulfonic Acids
sulfonic acid
Magnetization
Organophosphonates
magnetization
Chain length
Surface-Active Agents
Protons
Desorption
Ions
Transmission electron microscopy

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Yee, C., Kataby, G., Ulman, A., Prozorov, T., White, H., King, A., ... Gedanken, A. (1999). Self-assembled monolayers of alkanesulfonic and -phosphonic acids on amorphous iron oxide nanoparticles. Langmuir, 15(21), 7111-7115.

Self-assembled monolayers of alkanesulfonic and -phosphonic acids on amorphous iron oxide nanoparticles. / Yee, C.; Kataby, G.; Ulman, Abraham; Prozorov, T.; White, H.; King, A.; Rafailovich, M.; Sokolov, J.; Gedanken, A.

In: Langmuir, Vol. 15, No. 21, 12.10.1999, p. 7111-7115.

Research output: Contribution to journalArticle

Yee, C, Kataby, G, Ulman, A, Prozorov, T, White, H, King, A, Rafailovich, M, Sokolov, J & Gedanken, A 1999, 'Self-assembled monolayers of alkanesulfonic and -phosphonic acids on amorphous iron oxide nanoparticles', Langmuir, vol. 15, no. 21, pp. 7111-7115.
Yee C, Kataby G, Ulman A, Prozorov T, White H, King A et al. Self-assembled monolayers of alkanesulfonic and -phosphonic acids on amorphous iron oxide nanoparticles. Langmuir. 1999 Oct 12;15(21):7111-7115.
Yee, C. ; Kataby, G. ; Ulman, Abraham ; Prozorov, T. ; White, H. ; King, A. ; Rafailovich, M. ; Sokolov, J. ; Gedanken, A. / Self-assembled monolayers of alkanesulfonic and -phosphonic acids on amorphous iron oxide nanoparticles. In: Langmuir. 1999 ; Vol. 15, No. 21. pp. 7111-7115.
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