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Category Archives: Plasma Chemistry
Life in a vacuum
Giving back to the community personally and professional has always been important. The challenge however is making the time to have an impact. Through my involvement with groups such as AVS, SVEC and the SPE local chapter, I as well as my colleagues have been able to expose a diverse group of Bay Area kids and young adults to the varied career opportunities in the sciences, specifically surface modification and vacuum technology. One of my favorite events (tied with volunteering at the Maker Faire) is “Expanding your Horizons.” EYH is a not-for-profit organization that “inspires girls to recognize their potential and pursue opportunities in science, technology, engineering and mathematics.”
The following picture is from this year’s most recent event – with their permission of course. They were actively controlling the vacuum pump and chamber to “measure” the effect of a vacuum on a Peep marshmallow. This is always the highlight of the day…next to the shaving cream experiment!
It is incredibly rewarding to be in a room with curious young girls and expose them to my “life in a vacuum.”
Cramming in the name of science
About a year ago, I participated in a workshop, part of annual educational series called Microfluidics Regenerated: New Approaches, Applications, and Enabling Technologies. It was an excellent forum designed by BioDot to enhance learning about, and in some cases practice, nascent and existing technologies for designing new devices. The 2.5 day workshop included all meals allowing ample time to socialize with the people behind the knowledge and the audience.
All of the presentations were thought provoking – one that was out of the box was by Dr. Robert Hnasko, a scientist at the Berkeley, CA UDSA. He presented a method for rapid detection of toxins in microfluidic assays and blew many of us away with his rapid fire presentation backed by data and more data.
A few weeks after the event, he contacted me as recognized that plasma surface modification was an enabler for modification of substrates used in assays (such as ELISA and Western Blot). He was just wrapping up a book for the Methods in Molecular Biology series and asked if I would consider writing a plasma tutorial chapter. Of course, I said yes as glimmered by the idea of contributing to this technical resource book. I figured that it couldn’t be much more time consuming and difficult than writing a technical paper for a conference. Knowing that I couldn’t do it alone, I pinged my colleague Khoren Sahagian with a proposal. Khoren had been a writing partner for several years — in fact, our first meeting was to discuss a collaborative research program that led to a poster presentation and his eventual hire at Plasmatreat (my former employer). He said yes as quickly as I said yes to Dr. Hnasko. A lunch meeting ensued with Robert where he presented the form factor, allowed us to talk about our ideas, and provided excellent guidance. We talked a bit about the corn and greenhouses in sight of Buchanan…that I’ve been driving past for two decades plus.
Dr. Hnasko then SET A DEADLINE.
The evil deadline.
The one that sounds super reasonable at that time.
The one that you add to your calendar with reminders.
The one that sits in that special part of your brain where it is always present, in view, but not front and center.
You trust that it will move to the front and center location at the appropriate time. Well it didn’t. It stayed in that peripheral region out of the light. That deadline came and went and we didn’t have much to show (other than an awesome outline with enough sections and levels for a stand-alone tome on plasma). Our consuming work responsibilities and deadlines got in the way.
A NEW DEADLINE WAS SET.
That slipped (however the outline became realistic and manageable). Khoren and I tried to keep each other honest but there just wasn’t time in the day.
A FINAL DEADLINE WAS FIRMLY COMMUNICATED.
Again, we didn’t have time in the day so the creative late night college cram process began! Khoren would write from after dinner until 2 maybe 3 in the morning and I’d wake up at 4 to pick up where he left off before headed into the office. After a few weeks of this…at last we had a solid draft to present.
Well, one year later and I’m proud to say that the book is on the shelves (digital and physical). Order your book or chapter now at: Methods in Molecular Biology: ELISA Methods and Protocols
Oh, haven’t had to cram like that since.
A fishy story
Is it true that one of the first commercial uses of plasma ashing was to ablate fish to expose mercury contamination?
Sitting around the lunch table the other day, our chemist and founder, Stephen Kaplan, expanded on an early use of plasma for one of the first commercial applications: ashing fish to expose mercury (or other metals) to evaluate the impact of contamination from industry. While it seemed like a logical use of the technology, I couldn’t get my head around this as one of the first commercial applications….so did a bit of research and finally reached out to one of the experts in the field of vacuum technology: Donald Mattox. He confirmed that low pressure plasma ashing has been used for over 50 years for trace element analysis – an early use of replacing wet chemistry!
Don sent the following citations confirming the use:
1962: C. E. Gleit and W.D. Holland, “Use of electrically excited Oxygen for the low temperature decomposition of organic substrate” Anal Chem. Vol. 34 (11) pp 1454-1457
1977: M. Velodina, “Quantitative determination of Mercury in Organic materials by means of a low temperature, high frequency discharge plasma in oxygen” Analytical Letters 10(14) 1189-1194
And Don added one of his favorite Oxygen plasma cleaning stories (from his book “Foundations of Vacuum Coating Technology”)
When preparing to aluminize the Palomar mirror, John Strong notified the mirror polishers that he would be using a new cleaning technique using ‘a special fatty acid compound with precipitated chalk.’ When he arrived the ‘special fatty acid compound’ was Wild Root Cream Oil hair tonic (ad jingle: ‘You better get Wild Root Cream Oil, Charlie; It keeps your hair in trim; Because it’s non-alcoholic, Charlie; It’s made with soothing lanolin’). He stated, ‘In order to get glass clean you first have to get it properly dirty.’ The oil residue was ‘burned-off’ using an oxygen plasma in the vacuum deposition chamber. (From The Perfect Machine: The Building of the Palomar Telescope, Ronald Florence, pp 382-386, HarperCollins, 1994).
I’m assuming that the following US Patent from 1978 helps corroborate his story: 4088926: Plasma Cleaning Device (for cleaning organic contamination on optical surface)
I found this quite interesting and did some additional research that I would like to share with my readers:
Plasma, atmospherically, has been used professionally by museums and NASA to remove carbon contamination or char, selectively, as a restoration technique for fine art.
Before and after image of artwork cleaned by atomic oxygen.
Some later work of interest was published by Texas A&M: Used RF plasma to selective remove inorganic mater from paint and prevent damage to the substrate (rock). Organic components can then be analyzed and dated.
1992: Direct Radiocarbon Dating of rock Art. Radiocarbon, V 34, No. 3, 1992, P 867-872. J. Russ, M. Hyman and M. Rowe, TAMU.
I could go on and on and on… Plasma truly offers us a tremendous tool box for modification of myriad materials!
Plasma Treatment Basics for Coatings