We present for the first time a method for the preparation of magnetic halloysite nanotubes (HNT) by loading of preformed superparamagnetic magnetite nanoparticles (SPION) of diameter size ∼6 nm with a hydrodynamic diameter of ∼10 nm into HNT. We found that the most effective route to reach this goal relies on the modification of the inner lumen of HNT by tetradecylphosphonic acid (TDP) to give HNT-TDP, followed by the loading with preformed oleic acid (OA)-stabilized SPION. Transmission electron microscopy evidenced the presence of highly crystalline magnetic nanoparticles only in the lumen, partially ordered in chainlike structures. Conversely, attempts to obtain the same result by exploiting either the positive charge of the HNT inner lumen employing SPIONs covered with negatively charged capping agents or the in situ synthesis of SPION by thermal decomposition were not effective. HNT-TDP were characterized by infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), and ζ-potential, and all of the techniques confirmed the presence of TDP onto the HNT. Moreover, the inner localization of TDP was ascertained by the use of Nile Red, a molecule whose luminescence is very sensitive to the polarity of the environment. The free SPION@OA (as a colloidal suspension and as a powder) and SPION-in-HNT powder were magnetically characterized by measuring the ZFC-FC magnetization curves as well as the hysteresis cycles at 300 and 2.5 K, confirming that the super-paramagnetic behavior and the main magnetic properties of the free SPION were preserved once embedded in SPION-in-HNT.
An Approach for Magnetic Halloysite Nanocomposite with Selective Loading of Superparamagnetic Magnetite Nanoparticles in the Lumen / H.A.I. Hamza, A. Maria Ferretti, C. Innocenti, K.F. Fidecka, E. Licandro, C. Sangregorio, D. Maggioni. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - 59:17(2020 Sep 08), pp. 12086-12096. [10.1021/acs.inorgchem.0c01039]
An Approach for Magnetic Halloysite Nanocomposite with Selective Loading of Superparamagnetic Magnetite Nanoparticles in the Lumen
H.A.I. HamzaPrimo
;K.F. Fidecka;E. Licandro;D. Maggioni
Ultimo
2020
Abstract
We present for the first time a method for the preparation of magnetic halloysite nanotubes (HNT) by loading of preformed superparamagnetic magnetite nanoparticles (SPION) of diameter size ∼6 nm with a hydrodynamic diameter of ∼10 nm into HNT. We found that the most effective route to reach this goal relies on the modification of the inner lumen of HNT by tetradecylphosphonic acid (TDP) to give HNT-TDP, followed by the loading with preformed oleic acid (OA)-stabilized SPION. Transmission electron microscopy evidenced the presence of highly crystalline magnetic nanoparticles only in the lumen, partially ordered in chainlike structures. Conversely, attempts to obtain the same result by exploiting either the positive charge of the HNT inner lumen employing SPIONs covered with negatively charged capping agents or the in situ synthesis of SPION by thermal decomposition were not effective. HNT-TDP were characterized by infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), and ζ-potential, and all of the techniques confirmed the presence of TDP onto the HNT. Moreover, the inner localization of TDP was ascertained by the use of Nile Red, a molecule whose luminescence is very sensitive to the polarity of the environment. The free SPION@OA (as a colloidal suspension and as a powder) and SPION-in-HNT powder were magnetically characterized by measuring the ZFC-FC magnetization curves as well as the hysteresis cycles at 300 and 2.5 K, confirming that the super-paramagnetic behavior and the main magnetic properties of the free SPION were preserved once embedded in SPION-in-HNT.File | Dimensione | Formato | |
---|---|---|---|
ic-2020-01039g.R2_Proof_hi.pdf
accesso aperto
Tipologia:
Pre-print (manoscritto inviato all'editore)
Dimensione
4.23 MB
Formato
Adobe PDF
|
4.23 MB | Adobe PDF | Visualizza/Apri |
51_acs.inorgchem.0c01039con pag.pdf
accesso riservato
Tipologia:
Publisher's version/PDF
Dimensione
6.28 MB
Formato
Adobe PDF
|
6.28 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.