Ferrofluid preparation doubts

[fireace]

I have been trying to make a ferrofluid with magnetite of size around 1um, the results, not quite fluid alike.

 

 

It is the commercial available powder magnetite of ~1um,

i used about 1 spatula of powder, 20ml of baby oil(serves as carrier), 2ml of oleic acid(serves as surfactant), i put them on a hot plate magnetic stirrer, heat it up while stirring(without using magnetic stir bar as i can see the solution flowing because of the strong magnetic response of magnetite). after around 15 minutes i have a look on the solution, it seems quite similar to the ferrofluid seen online.

i place a magnet near it, spikes are forming, but the sad part is that, it separates into two forms, ie. the wet magnetite and transparent liquid solution(of baby oil and oleic acid), i can safely decant away the liquid without losing any of the magnetite

after the removal of magnet, the wet magnetite will not remains back to the fluid form as the carrier liquid is already separated from it

 

i took some photos after decanting the extra liquid,

without magnetic field

 

with magnetic field

 

after magnet has been removed

 

the wet magnetic, without the presence of carrier liquid, can't even gets back into relaxed shape

 

 

i have been trying with various combination of carrier medium including acetone, kerosene, with coating of oleic acid, without coating, volume of carrier, volume of surfactant,

i even tried synthesizing a nano sized magnetite and tried with same steps to prepare the ferrofluid,

all attempts are in vain

 

 

 

so here comes the question, how should i prepare a real ferrofluid, with the materials i have, namely ~1um size magnetite powder and also nano scaled synthesized magnetite?

did i make any mistakes on preparing it, or perhaps i am missing any secret little steps?

 

thanks for the help!

[le_malin]

I've ordered Oleic Acid, Fe3o4 (used in thermite) and got Kerosene at the local hardware store, thinking I could make my own ferrofluid - the products are still in transit.

 

But now I read your post and... yeah. I'm also having doubts.

 

I was thinking I could just mix the iron with the oleic acid, then add the kerosene... but I think there may be some wizardry involved here (aka. science).

 

There are no recipes that I could find which have only these basic ingredients...

 

For me, my biggest concern is coating the iron with oleic acid - can you just stir them together? Or does the oleic acid need to be heated? Should I mix oleic acid and amonia, heat it, add the iron, let the amonia evaporate, cool the solution, then add the kerosene?...

 

I hope someone reads this still... the post is quite old...

 

I have been trying to make a ferrofluid with magnetite of size around 1um, the results, not quite fluid alike.

 

 

It is the commercial available powder magnetite of ~1um,

i used about 1 spatula of powder, 20ml of baby oil(serves as carrier), 2ml of oleic acid(serves as surfactant), i put them on a hot plate magnetic stirrer, heat it up while stirring(without using magnetic stir bar as i can see the solution flowing because of the strong magnetic response of magnetite). after around 15 minutes i have a look on the solution, it seems quite similar to the ferrofluid seen online.

i place a magnet near it, spikes are forming, but the sad part is that, it separates into two forms, ie. the wet magnetite and transparent liquid solution(of baby oil and oleic acid), i can safely decant away the liquid without losing any of the magnetite

after the removal of magnet, the wet magnetite will not remains back to the fluid form as the carrier liquid is already separated from it

 

i took some photos after decanting the extra liquid,

without magnetic field

 

with magnetic field

 

after magnet has been removed

 

the wet magnetic, without the presence of carrier liquid, can't even gets back into relaxed shape

 

 

i have been trying with various combination of carrier medium including acetone, kerosene, with coating of oleic acid, without coating, volume of carrier, volume of surfactant,

i even tried synthesizing a nano sized magnetite and tried with same steps to prepare the ferrofluid,

all attempts are in vain

 

 

 

so here comes the question, how should i prepare a real ferrofluid, with the materials i have, namely ~1um size magnetite powder and also nano scaled synthesized magnetite?

did i make any mistakes on preparing it, or perhaps i am missing any secret little steps?

 

thanks for the help!

[Nuclear_solution]

I've tried to make ferrofluid a few times, and there's a few things that I've ran into problems with using these ingredients. Firstly, the hematite comes from stepped down Iron3Cl. You have to reduce it to Iron2Cl. Another issue is that the layers don't separate into distinct species. When I do the experiment i find that you need to have a large amount of iron particles in the solution, i.e my thoughts are that we need to have a super saturated solution. The next time I do this I'm going to try and heat the solution sllllllooooowwwwllly and add everything over the course of a few hours. In this time I'm hoping to get a super saturated iron2cl solution.

[limsgp]

 

Anyone tried using citric acid as surfactants?

Just wondering.. There seems to be some studies on it. But wouldn't the acid react with the Fe3O4 (a base)?