Ferrofluid-MWCNT hybrid nanocomposite in liquid state

Patent metadata

Field	Value
Publication number	US-9704628-B2
Application number	US-201514747172-A
Country	US
Kind code	B2
Filing date	Jun 23, 2015
Priority date	Jun 23, 2014
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A water based double surfacted ferrofluid having magnetite nanoparticles (2-18 nm) coated with primary and secondary surfactants is synthesized. On the other hand, an aqueous dispersion of functionalized MWCNT (diameter=14-18 μm, length=1.6-2.5 μm) is prepared by acid treatment. A hybrid solutions in different v/v ratios yielded stable dispersions having both nanoparticles and nanotubes in itself behave as one system. The synthesized hybrid fluid show magnetic response and self-sustained homogeneity of in presence of magnetic field. In addition, the hybrid fluids exhibits a long term sedimentation and magnetic stability which enables one to use them for various applications like MRI, EMI shielding, energy conversion etc.

First claim

We claim:

1. A Fe 3 O 4 -MWCNT hybrid nanocomposite in liquid state comprising water based ferrofluid in fixed volume concentration and MWCNT, wherein the water based ferrofluid ranges between 1 to 30 in volume to 1 volume of MWCNT.

2. A process for the preparation of Fe 3 O 4 -MWCNT hybrid nanofluid comprising the steps of:
i. mixing ferrous sulphate heptahydrate and ferric chloride in the ratio 1:2 with a mixture of 25% (v/v) ammonia and in presence of primary surfactant and emulsifier followed by heating at temperature in the range of 30 to 60° C., magnetic decantating and washing to obtain a mixture;
ii. adding secondary surfactant dissolved in water at temperature in the range of 30 to 50° C. in the mixture as obtained in step (i) followed by centrifuging to obtain Fe 3 O 4 dispersion;
iii. treating MWCNTs with HNO 3 and heating at temperature in the range of 25 to 30° C. for period in the range of 150 to 180 min followed by filtering and washing to obtain dried MWCNTs;
iv. treating dried MWCNTs as obtained in step (iii) with HNO 3 followed by sonicating; heating at temperature in the range of 80 to 90° C. for a period in the range of 55 to 65 hours, cooling filtering and washing to obtain filtered product;
v. dispersing the filtered product as obtained in step (iv) in water to obtain MWCNT dispersion;
vi. mixing dispersions as obtained in step (ii) and (v) in the volume ratio of the dispersion obtained in step (ii) to the dispersion obtained in step (v) ranges between 1 to 30 using mechanical stirring to obtain Fe 3 O 4 -MWCNT hybrid nanofluid.

3. The process as claimed in claim 2 , wherein emulsifier used is acetone.

4. The process as claimed in claim 2 , wherein primary surfactant used is oleic acid.

5. The process as claimed in claim 2 , wherein secondary surfactant used is sodium oleate.

6. The process as claimed in claim 2 , wherein ion-dipole interaction between Fe 3 O 4 -MWCNTs leads to stable suspension.

Assignees

• Council Scient Ind Res

Inventors

• Pant Rajendra Prasad
• Shankar Ajay
• Jain Komal
• Sonia
• Chand Mahesh

Classifications

• H01F1/445 Primary

  the magnetic component being a compound, e.g. Fe3O4 (H01F1/447 takes precedence) · CPC title