We used electric fields very successfully to achieve exactly what you want.

Please refer to the attached publications.

Article Electrospinning of aligned fibers with adjustable orientatio...

Article Electrodynamic control of the nanofiber alignment during ele...

One‐step fabrication of branched poly(vinyl alcohol) nanofibers by magnetic coaxial electrospinning

Huijun Wu

Jintu Fan

Xianfu Wan

Ning Du

Journal of Applied Polymer Science (Impact Factor: 1.4). 07/2012; 125(2). DOI: 10.1002/app.35585

ABSTRACT Branching has been emerging in 3‐D interconnecting building blocks. Branched and hyperbranched poly(vinyl alcohol) (PVA) nanofibers were fabricated by coaxially electrospinning two‐liquids under an alternating magnetic field in a facile

check this paper....they developed parallel fibers using similar technique...

Hi Aisha,

Magnetic fields are MUCH weaker compared to electric fields if you want to achieve alignment. Also, my guess is that the fluid dynamic forces (which removes any magnetically induced alignment) you expose your solution during electospinning is multiple times larger than the magnetic force causing alignment.

We have used very strong magnetic fields, around 11-14 Tesla, to achieve magnetic alignment in iron containg clay disperions inside 5 mm NMR tubes:

http://pubs.rsc.org/en/Content/ArticleLanding/2014/SM/C4SM00315B#!divAbstract

Electrical alignment might be an better option if you want to do electorspinning, but as you have added fe304 I understand that you seek a magnetic effect. My guess is that your disperion dries to fast during electrospinng to have time to align in a magnetic field. I do not know the exact purpose with your project, still, I would have tried something else than electospinning to achive magnetic alignmemnt in your solution/disperion, for example a sol-gel method as we do in the article I link to above. In that way you can give the fe304 particles (it must be colloidal particles as dissolved fe304 will not align) enough time to align before the the system goes from a dispersion to a gel which freezes the magnetic alignment of the system. The gelation could be tuned to take the right time by adding the right amount of destabilizer (salt?) or crosslinker, which type would be good to use depends on you system.  

You might be able to do fibers that have magnetic and shear induced alignmnet with a process similar to this one, the drying of the fiber can be slower in this case:

http://www.nature.com/ncomms/2014/140602/ncomms5018/full/ncomms5018.html 

Good luck!

Chris

A rotating drum target will give you aligned nanofibers. Simply use a small motor attached to a round shaft.

As Christoffer Abrahamsson answered, the electrical field will rule over the weak magnetic field you are trying with your magnets. You can't even compare them.   Besides, the control over the flying path is very difficult as your charge density is contiously changing and your magnetic fiels also.  Go for an aproach where your collector promotes the alignment: rotating drum, fended collector, spiked collector. All of them work very well and are easy to build: DIY with a couple of metal pieces and simple "crocodile" connections.

Dear Parmiss Mojir Shaibani,

In my experience a simple drum target will give you aligned nanofibers to a limited degree of alignment. Thus the question is what you consider aligned. In principle with only a rotating target without taking special care to optimize the electric field distribution of the setup it is not possible to get perfectly aligned fibers via electrospinning. To get aligned fibers you have to match the velocity of the electrospinning jet's z-component (the component in direction of the target) in the order of m/s with the rotional speed to get rid of the buckling instability upon impingement of the jet on the surface. However, when you do not design your electric field appropriately you will still have velocity components of the jet in x-direction (perpendicular to the target, in the axis of the rotation) and thus you cannot get all fibers in parallel. Thus you have to ultimately decrease the ratio between x component and z component. In principle this is also possible with a roller only but would require very very fast speeds and thus is much more efficiently done by designing the electric field appropriately.   

Please see Figure 7 in the attached publication for a good demonstration of the occuring effects.

Article Electrospinning of aligned fibers with adjustable orientatio...

If you have a very high speed (200-300 rpm) rotating mandrel. But you should have the mandrel coming from the side across the face of the electrospinning target; therefore, the direction of the mandrel spinning is parallel to the direction your espinning needle is pointing.

Hi Paul, you are talking about horizontal set-ups, right?

Yes! That's the word I was looking for. Sorry, it's early.

Hi Paul, 200-300rpm really doesnt sound high, did u mean 2000-3000? Check the attached pic, is that the kind of setup u r talking about?

The minimum speed of the cylinder will depend a lot on the lenght of your flying pathway, on the diameter of the fibres, and, most important, it will depend on the diameter of your collecting cylinder. Try a a couple of speeds and see the trend for your fibres with your set-up. For most  polyesters, for instance, 200rpm with a 10cm diameter drum with a flying path of 25cm, you perfectly align them.

Dear Aisha,

this paper can be help you and also can be download from Researchgate:

Christian Grasl et al., Electrodynamic control of the nanofiber alignment during electrospinning. APPLIED PHYSICS LETTERS 102, 053111 (2013).

Best regards,

Carlos Fuhrhop

Article Electrodynamic control of the nanofiber alignment during ele...

Dear Aisha,

Aligned nanofibers were continuous fibers like a single thread rolled out from a  bundle , for getting aligned nanofibers you have to make a modification in your electrospinning setup as given in the literature [ PFA ].  which describes information on circuitry to be installed in Espin instrument to obtain aligned nano fibers . Actually they are using 3 power supply [ 1. for needle tip (+ve) , 2. for auxiliary electrode (+ve to repel to produce coulomb force ) , 3. for drum collector ( - ve ) ] . You can check the schematic diagram in Page 4 and potential values [ i have highlighted those information for your reference ] .

In your case , as per the description , there are some literature available for getting aligned nanofibers with the help of magnetic field. As per the information , the position of magnetic field and field strength is very important to get aligned nanofibes. Also , the loading concentration of your magnetic nanoparticles should be fine tuned [ particle size , magnetization and colloidal stability ] for proper dispersion and emerge as fibers in the form of  encapsulated MNP or MNP decorated nanofibers.

chk the below link......

http://pubs.rsc.org/en/content/articlelanding/2013/ra/c2ra22726f#!divAbstract

http://pubs.rsc.org/en/content/articlelanding/2011/sm/c0sm00762e#!divAbstract

all the best.......