Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Suspensions and Colloids

Ishan Wathuthanthriiwathuth@stevens.edu

Department of Mechanical Engineering

Stevens Institute of Technology

New Jersey, USA

Nano and Microfluidics Laboratory (NMfL)

Suspensions• Particles larger than ~1000nm.• Separated by gravity.• Examples (sand/water, dust/air)

Nano and Microfluidics Laboratory (NMfL)

Making An Interesting Suspension

Mix two parts cornstarch to one part water.• 100ml cornstarch (large beaker)• 50ml water (small beaker)• Place cornstarch into a ziploc bag and add water.• Close bag and mix.

Write down some characteristics of this suspension.

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Colloids

• Particles upto ~100nm.• Cannot be separated by gravity

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Example of a Colloid- Ferrofluids• Ferrofluids- “ferro” iron.• Polarized in a magnetic field.• Colloidal mixture of iron particles suspended in a carrier fluid.• Generally particles ~10nm.

Reference- L.Mao and H. Koser.

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

History

• Developed by NASA in the 1960’s.• Method of controlling fluids in space.

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Review of Magnetism

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Electromagnet

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Applications of Ferrofluids

• Liquid seals in bearings. Used in hard drives/ o-rings.

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Speakers

• Used for and cooling around coils.

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Dampening

• Internal dampers in shock absorbers and stepper motors etc.

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Biomedical Application

• Magnetic cell separation chambers

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

• Target delivery agents.

Nano and Microfluidics Laboratory (NMfL)

Nano and Microfluidics Laboratory (NMfL)

Telescopes for Astronomy

• Research conducted in using ferrofluids for liquid mirrors.

http://www.newscientist.com/article/dn15154-morphing-mirror-could-clear-the-skies-for-astronomers.html?feedId=online-news_rss20

Nano and Microfluidics Laboratory (NMfL)

Thank you.Questions?