On Apr 29, 2009, at 22:17, Sheng Zhang wrote:

> I think job market for microfluidics is very limited...unless you want
> to go to academia as your career.


Really?  I will admit that I haven't looked hard at that subfield and
don't have the most up-to-date information, but I had been under the
impression that microfluidics were looking very promising for
commercial biotech, especially in applications such as micro-PCR,
combinatoric analysis, and other "lab-on-chip" biochemical devices
where the ability to perform many parallel reactions on tiny volumes
of fluid would be a huge benefit in speed and cost.  (Not going to
shill for companies here, but a quick google search for "commercial
microfluidic" yields a pretty rich list of products.)

Also note that microfluidics can overlap with inkjet technology,
which is seeing quite the surge in areas such as 3-D printing and
nonlithographic planar microfab.

On the other hand, it's certainly possible I'm overlooking problems
in scale-up and manufacturability of these systems; that's certainly
a perennial "gotcha" in this field which can prevent a device making
the transition from PhD thesis to commercial product.

To the original poster:

> I'm now puzzled at choosing my graduate field especially at
> microfluidics and power MEMS. It will be very nice if anyone can
> give me some advise on the following questions:
>
> 1) How do mechanical engineers' work differentiate from others,
> especially those in materials, chemistry and bioengineering? I find
> most of the distinguished work was done by the latter. If I choose
> microfuidics as my future career, will I be making a wise choice?


I think the answer to this question depends on "what do you do with
your time in grad school?"  Also, realize that it's very hard to make
general statements about grad studies at all universities; there's
huge variation from school to school.

Right now, MEMS is a very interdisciplinary field.  For example, at
MIT, we have people doing MEMS work based in the electrical
engineering, mechanical engineering, materials science,
bioengineering, biology, and aero/astro engineering.  (Off the top of
my head; I may be missing some!)  I can't speak for how other schools
are organized, but most of the people who end up doing MEMS here end
up doing quite a bit of "cross-training" - even people in the EE
department will have to learn mechanics if they want to be able to
competently design moving parts, for example!  So on one level, no
matter which department you end up studying in, you should have the
opportunity to do cross-disciplinary studies if you want to.
However, your department will influence the "focus" of your work.
Here at MIT, for example, the mechanicals tend to focus more on
complex micro-machines (micro-turbine, micro-positioning stages,
etc.); the electricals tend to focus on fields like power MEMS and
optical MEMS, and so on... but that's only a tendency, not a rule.
More relevant is the focus of each professor - if an EE professor
wants to work on micro-gear trains, and can get grant funding to do
it, that's what will happen.

So most importantly: Don't necessarily think in terms of "what
department?", but rather "what professors do I want to work with?"
You may find that your interests are best matched in the mech-E
department of school X, but in the bioengineering department of
school Y.

To a certain extent, it also depends on what kind of work you want to
do.  You mention "distinguished" work, but what does that actually
mean?  Work like the MIT micro-turbine, or Sandia's incredible MEMS
gear chains, is quite distinguished in the engineering fields, and
falls squarely into the category of "mechanical engineers working on
MEMS".  In contrast, a larger portion of the work coming out of the
materials and chemistry fields will be in the science of micro/
nanofabrication - growth, deposition, and etch techniques, active
materials, and improved processes and materials for electronic
manufacturing.  You'll see those people publishing techniques for
nanowire growth, self-assembly, all kinds of work on, say, carbon
nanotubes - but not as much on complex device design and fabrication.

So, do you want to be a scientist, focusing more on fundamentals, or
an engineer, focusing more on applications?  Both choices have plenty
of opportunities, and there is plenty of overlap between the two, but
it's worth thinking about which you think is a better match for you.

Also, understand that your PhD doesn't have to define you for the
rest of your life.  People can and do change focuses after a PhD -
postdoc work is a common time to do that.  Obviously, that change can
be made easier if you did some relevant work in school (say, while
working on that microfluidics PhD you also happened to collaborate on
some silicon-MEMS projects), but even if not, a good publication
history and demonstrated ability to produce results will go a long way.

Finally, one last crazy thought - if you think you might be
interested in microfluidics or power MEMS, why not look for a project
that combines the two?  Just found this with a quick lit search, I'm
sure there are more:

"A microfluidic-electric package for power MEMS generators"

http://www.mems.gatech.edu/msmawebsite_2006/publications/
publication_list_files/2008/A%20Microfluidic-Electric%20Package%20for%
20Power%20MEMS%20Generators.pdf

Good luck!