Poster_SheongWei_NG_Synthesis and stabilisation of SPIONP sol
1
Synthesis and stabilisation of the superparamagnetic iron oxide nanoparticles (SPIONP) sol Sheong Wei NG Cologne University of Applied Sciences, Cologne/Germany, 2015 Superparamagnetism (SP) SP describes the behaviour of certain type of materials by which large magnetisation (M) is induced when an external magnetic field is applied on the materials and the generated magnetic field has the same magnetic direction (H) as the external applied magnetics field. Figure 1 illustrates the difference between ferromagnetism, paramagnetism and superparamagnetism. Nanoparticles exhibit this behaviour at room temperature. Stabilisation of the SPIONP sol Coprecipitated SPIONP can be electrostatically (a) and sterically (b) stabilised to prevent agglomeration. Nitric acid (HNO 3 ) and Tetramethylammonium hydroxide (TMAOH) electrostatically stabilise SPIONP. Conclusion • The SPIONP sol can be synthesised with coprecipitation method and stabilised with HNO 3 or TMAOH. • The synthesised sols behave like ferrofluid. • Temperature and ultrasound have no effect on the sols. • Change of pH of the sols causes the SPIONP to agglomerate. Because the charged ions, which electrostatically stabilise the SPIONP, are neutralised by the added oppositely charged ions. References [1] Anon: Superparamagnetism: limits and applications, Nanotechnol 7 (2007) 1828-1836 [2] A. Andrade, R. Ferreira, J. Fabris, R. Domingues: Coating nanomagnetic particles for biomedical applications, in B.S. Prof. R. Fazel (Eds): Biomedical engineering – Frontiers and challenges, InTech, Croatia, 2011, pp. 157-176 Fig. 1: The difference between ferromagnetism, paramagnetism and superparamagnetism [1] (a) (b) Fig. 2: Electrostatic (a) and steric (b) stabilisation of SPIONP [2] Note: FeCl 3 ∙6H 2 O - Iron (III) Chloride hexahydrate FeCl 2 ∙4H 2 O - Iron (II) Chloride tetrahydrate Note: HCl – Hydrochloric Acid Synthesis of HNO 3 stabilised SPIONP sol Synthesis of TMAOH stabilised SPIONP sol Stability of the sols against Ultrasound Ultrasound treatment HNO 3 stabilised SPIONP sol TMAOH stabilised SPIONP sol Ultrasound treatment • The sols reacted similarly to the magnet after the ultrasound treatment. • Ultrasound has no effect on the sols. Stability of the sols against Temperature 20 °C 40 °C 60 °C 80 °C HNO 3 stabilised SPIONP sol TMAOH stabilised SPIONP sol Temperature • The sols reacted similarly to the magnet after immersion in water baths with different temperatures. • Temperature has no effect on the sols. Stability of the sols against pH change HNO 3 stabilised SPIONP sol TMAOH stabilised SPIONP sol Addition of NaCl Addition of HCl The SPIONP agglomerate after the addition of sodium chloride (NaCl). Because the H + ions from the HNO 3 , which electrostatically stabilised the NP, was neutralised by the added Cl - ions. The SPIONP agglomerate after the addition of HCl. Because the OH - ions from the TMAOH, which electrostatically stabilised the NP, was neutralised by the added H + ions. MS : Saturation magnetisation MR : Remanent magnetisation Ferromagnetism Paramagnetism Superparamagnetism FeCl 3 •6H 2 O 2.16 g FeCl 2 •4H 2 O 0.795 g Distilled water 100 ml Dispersion with black precipitate Ammonium hydroxide 5 ml Under stirring Black precipitate Seperation with magnet Black precipitate Wash with distilled water (3X) Black sol (Ferrofluid) Distilled water 10 ml 1 M HNO 3 10 ml 1 M FeCl 3 •6H 2 O (in 2 M HCl) 10 ml 2 M FeCl 2 •4H 2 O (in 2 M HCl) 2.5 ml Orange solution Sol with black precipitate TMAOH (25 % w/w) 21 ml Under stirring Black sol (Ferrofluid)
-
Upload
sheongwei-ng -
Category
Documents
-
view
68 -
download
1
Transcript of Poster_SheongWei_NG_Synthesis and stabilisation of SPIONP sol
Synthesis and stabilisation of the superparamagnetic iron oxide nanoparticles (SPIONP) sol
Sheong Wei NG Cologne University of Applied Sciences, Cologne/Germany, 2015
Superparamagnetism (SP) SP describes the behaviour of certain type of materials by which large magnetisation (M) is induced when an external magnetic field is applied on the materials and the generated magnetic field has the same magnetic direction (H) as the external applied magnetics field. Figure 1 illustrates the difference between ferromagnetism, paramagnetism and superparamagnetism. Nanoparticles exhibit this behaviour at room temperature.
Stabilisation of the SPIONP sol Coprecipitated SPIONP can be electrostatically (a) and sterically (b) stabilised to prevent agglomeration. Nitric acid (HNO3) and Tetramethylammonium hydroxide (TMAOH) electrostatically stabilise SPIONP.
Conclusion • The SPIONP sol can be synthesised with coprecipitation
method and stabilised with HNO3 or TMAOH. • The synthesised sols behave like ferrofluid. • Temperature and ultrasound have no effect on the sols. • Change of pH of the sols causes the SPIONP to agglomerate.
Because the charged ions, which electrostatically stabilise the SPIONP, are neutralised by the added oppositely charged ions.
References [1] Anon: Superparamagnetism: limits and applications, Nanotechnol 7 (2007) 1828-1836 [2] A. Andrade, R. Ferreira, J. Fabris, R. Domingues: Coating nanomagnetic particles for biomedical applications, in B.S. Prof. R. Fazel (Eds): Biomedical engineering – Frontiers and challenges, InTech, Croatia, 2011, pp. 157-176
Fig. 1: The difference between ferromagnetism, paramagnetism and superparamagnetism [1]
(a) (b)
Fig. 2: Electrostatic (a) and steric (b) stabilisation of SPIONP [2]
Note: FeCl3∙6H2O - Iron (III) Chloride hexahydrate FeCl2∙4H2O - Iron (II) Chloride tetrahydrate
Note: HCl – Hydrochloric Acid
Synthesis of HNO3 stabilised SPIONP sol Synthesis of TMAOH stabilised SPIONP sol
Stability of the sols against Ultrasound
Ultrasound treatment
HNO3 stabilised SPIONP sol TMAOH stabilised SPIONP sol
Ultrasound treatment
• The sols reacted similarly to the magnet after the ultrasound treatment.
• Ultrasound has no effect on the sols.
Stability of the sols against Temperature
20 °C 40 °C 60 °C 80 °C
HNO3 stabilised
SPIONP sol
TMAOH stabilised
SPIONP sol
Temperature
• The sols reacted similarly to the magnet after immersion in water baths with different temperatures.
• Temperature has no effect on the sols.
Stability of the sols against pH change
HNO3 stabilised SPIONP sol TMAOH stabilised SPIONP sol
Addition of NaCl
Addition of HCl
The SPIONP agglomerate after the addition of sodium chloride (NaCl). Because the H+ ions from the HNO3, which electrostatically stabilised the NP, was neutralised by the added Cl- ions.
The SPIONP agglomerate after the addition of HCl. Because the OH- ions from the TMAOH, which electrostatically stabilised the NP, was neutralised by the added H+ ions.
MS : Saturation magnetisation MR : Remanent magnetisation
Ferromagnetism
Paramagnetism
Superparamagnetism
FeCl3•6H2O 2.16 g
FeCl2•4H2O 0.795 g
Distilled water 100 ml
Dispersion with black precipitate
Ammonium hydroxide
5 ml
Under stirring
Black precipitate
Seperation with magnet
Black precipitate
Wash with distilled water (3X)
Black sol(Ferrofluid)
Distilled water 10 ml1 M HNO3 10 ml
1 M FeCl3•6H2O (in 2 M HCl)
10 ml
2 M FeCl2•4H2O (in 2 M HCl)
2.5 ml
Orange solutionSol with black
precipitate
TMAOH (25 % w/w)
21 ml
Under stirring
Black sol(Ferrofluid)
