Material Uses Insect Technology to Stay Dry Under Water

Let's start with the basics, shall we?

In general water is bad for the long-term durability of most surfaces - especially metal surfaces.

Water molecules hold together pretty well. I've even seen (and highly endorse) magnets that show this.

Water molecules have some volume, especially when they hold to other water molecules.

(Now, the tougher step...)

If you can make bumps...pores...posts...something on the surface of a material that leaves spaces too small for water drops (clumps of water molecules) to go into, the surface of the material will stay dry.

Seriously...like forever dry...not from a coating that will eventually wear off...permanently dry (or at least for four months as the early research shows)...

Left column: (top) Polymer/HFS (NC1) composite coating on aluminum substrate, (bottom) silicon square microposts. Middle column: (top) zinc oxide nanorods on silicon substrate, (bottom) silicon nanowire forest. Right column: (top) silicon microgrooves, (bottom) silicon nanograss.

See those scanning electron micrographs (SEM) above? They're from an article on Nature's website. Each surface was tested to see how long it would resist being wetted when immersed in water (then in water that had been thoroughly degassed - to make sure it wasn't gas bubbles being trapped that resulted in the lack of wetting).

Left: Wetted surface with 25 μm pillar spacing. Middle: Wetted surface with 5 μm pillar spacing. Right: Dry surface with sub-micron pillar spacing. Abbreviations: Frozen water (H₂O), Silicon substrate (Si)

And there you can see their results. Make the pillars wide enough to leave 25 microns of space, get a wet surface...5 microns, still wet...less than one micron, dry...forever dry...perfectly dry.

There's a nice summary of the article on IFLScience's website, but you do, as always, run into the issue of that F in the web address...

Raw Craft with Anthony Bourdain - Episode Four: Bob Kramer

Well, yeah, who doesn't turn a meteorite into a chef's knife in their spare time?

Bourdain visits with Bob Kramer, a master chef's knife maker who goes through the smelting, forging, and heat treating of some pretty spectacular knives.

At about 5:38 (explanation starts) then at 6:18 (actual visual) is one of the - if correctly described - most stunning things I've ever seen in material science. Kramer explains that there is a 'shadow' that moves through the steel as it - as I understand - undergoes the phase change from FCC to BCC, squeezing the carbon into the harder, BCC form of iron.

I am currently looking for confirmation from a second source, however, that what we see is actually what Kramer says it's showing.

♡DIY: School Pride Plastic Cuffs {Back To School}

Our students love the shrinky dinks. The success rate is pretty high (not 100% because of the curling and touching that the video maker above mentions), and it's a simple project. There are lots of fun creations that can be made (even entire books about the projects).

I've never tried to twist or bend the shrinky dink when it first comes out of the toaster oven, admittedly. Usually I'm trying to flatten it down as much as possible.

A new type of bandage will draw out bacteria and speed healing

Personally, I like the bacon bandages available from Archie McPhee. I will warn you, however - and this comes from someone who has bought a full box of those bandage tins - that their sterile wrapping isn't as well made as are the name-brand Band Aids. If you leave the bacon bandages for a few years, the wrapping comes apart.

I'm thinking, though, that any bandages made out of the material from this article will be of slightly higher quality than were those bacon bandages.

The basics - including the graphic above from the ACS-published article - are that...

[t]he nanofibre mesh is created using a technique called electrospinning, in which polymer filaments 100 times thinner than a human hair are squeezed out of an electrified nozzle.

The resulting fibre is then coated in compound called allylamine, which Abrigo has found makes a range of different bacteria quickly attach to it.

The bandages have been tested on liquid media and directly onto agar plates but not yet on actual wounds.

From the ACS abstract - and possibly most interesting from a material perspective, "[f]iber diameter was shown to affect the ability of bacteria to proliferate within the fibrous networks, depending on cell size and shape. The highest proliferation rates occurred when fiber diameter was close to the bacterial size. Nanofibers were found to induce conformational changes of rod shaped bacteria, limiting the colonization process and inducing cell death. The data suggest that simply tuning the morphological properties of electrospun fibers may be one strategy used to control biofilm formation within wound dressings."

How cool...

Explorations in Materials Science (discontinued)

About twenty years ago Arthur Ellis, Wisconsin chemistry professor, visited our senior chemistry class at Wabash College. He was a friend either of Richard Dallinger, one of our chemistry professors at Wabash and one of my advisors, or of David Phillips, another chemistry professor and husband of Pru Phillips under whom I did my student teaching.

Dr Ellis presented information about light-emitting diodes, teaching us about p-gaps, n-gaps, and lots of other stuff that I don't really understand anymore but that I need to learn again now that it's in the recently-revised AP chemistry curriculum.

At the time, though, Dr Ellis took some time to speak to me, the lone chemistry teacher in training in the senior class at Wabash. He was particularly excited about the Institute for Chemical Education (ICE) at the University of Wisconsin. They had at that point recently published Teaching General Chemistry: a materials science companion (see the yellow book down and to the right), and Ellis (or maybe Pru, I can't remember) gave me a copy of the book. I filed it away somewhere, kept it in my supplies, and forgot that it existed for ten or fifteen years. Then one of the master teachers in the ASM program mentioned the book, and I bought a copy - with no memory of already having a copy somewhere in my supplies already.

Recently I went looking at ICE's website seeing what was still around there for purchase and use. One item in particular caught my attention, something called the Explorations in Material Science kit (the image up top is of that kit). It looks to be a trio of silicon molds allowing for the creation of nine roughly identical samples for, I assume, subsequent testing. The kit seems to also include a pound of tin shot (at least that's what's available as replacement supplies from their catalog.


The idea of materials samples in identical shapes, sizes, thicknesses, but widely varying compositions (different metals, various polymers, ceramics, glasses, composites) for testing is something I would love to have for my material science classes.

Does anybody out there have one of these Explorations in Material Science kits out there? Is it worth hunting?

The Point of a Monument: A History of the Aluminum Cap of the Washington Monument

The Washington Monument was capped with aluminum in 1884 because aluminum was among the most valuable metals at the time, and the use of aluminum as an apex for the monument was a way for the United States to demonstrate its material science and industrial primacy in the world.

At least that's the story I tell in my material science class and in my summer workshops.

George Binczewski, however, tells a different story in his article "The Point of a Monument: A History of the Aluminum Cap of the Washington Monument." In the article, Binczewski recounts the story of how aluminum was chosen, cast, and subsequently refurbished. Apparently aluminum was not the first choice, and material selection had more to do with use as a point to the lightning protection system.

That isn't nearly as exciting a story as the mic drop version of material science. "We have aluminum. You don't. Deal with it, punks. US out."

Sadly, though, it just might be truer. I'm going to have to adjust my patter again.

By the way, you can check out the aluminum apex actually looks - as of the Monument's 2013, post-earthquake check-up, anyway - in this pic (source: Wikipedia).

And here's a look at the most metal version of the apex in its era of having a copper jacket (visible just above at the base of the apex) but without its temporary copper spikes to further its job as a lightning rod. (Source: Phillip C Marshall)

Pic up top is from Red Ice Creations.

Eisenmann Camp 2015 - an inside view

The Eisenmann student material camp takes place each summer at Materials Park, and this summer I was thrilled to send one of my students up for the week-long, zero-cost (other than getting himself there) introductory week of materials education.

Upon his return, Lucas was even willing to - admittedly, at my request - write up a bit about his time under the dome so all of you could see what the student camps are like.

Check it out...

Eisman Material Science Camp

I am a former student of the marvelous Mr. Lonnie Dusch. I love the subject of chemistry, which he just happened to teach, He recommended that I apply for the Eisman Material Science Camp for students because it was chemistry related, and it involved things that he taught me outside of my class. I thought this would be a great experience for me to meet new people and learn more about the subject I love. I applied and was accepted to attend the camp. I went to the camp over the summer and spent one week there. Students were supposed to meet at the hotel that we were all staying at. Once I arrived I noticed just how nice of a hotel it was. It had an arcade, a pool, and its own restaurant.

One of the great parts was that I didn’t have to pay for any of it. It was all free. Getting accepted into the program was considered a scholarship which was used to pay for almost everything during the week. This meant that our meals were free, the hotel was free, the equipment and supplies we used were free. The only thing we did have to pay for was the games in the arcade. After we got to the hotel and met our roommates, we went to ASM material parks. Most of the students, including myself, had seen pictures of it, but never seen it in person. It was an average sized building with a garden full of plants and the ore of almost every metal. All this was sitting under the largest geodesic in the world. It was an enormous aluminum structure and we all stared at during the sunset.

After we arrived we ate dinner and were broken up into groups. Each group was assigned a mentor. After this we went in our groups and took different things apart, mainly by breaking them. Next we went back to our hotel.

The following day we presented what we found the night before from breaking things. After this our mentors presented their groups with projects for the week. All of the projects were determining how and why something broke. Our group’s project was to determine while a weld broke in an odd way during a bend test. We made guesses on the first day but had no evidence to prove it, so throughout the week my group did several different things to prove our theories. The first thing we noticed is that we couldn’t see the fracture surface of our project very well. So what do we do? Break it more of course! We made the metal very brittle by cooling it with liquid nitrogen. After this we took a few pictures with a microscope.

For the rest of the week we continued to do different tests to prove our theories. We had access to an electron microscope which we used to view very small features of the fracture surface. We searched for small craters that would indicate impurities in the metal but we didn’t find any. We also used the electron microscope to determine the type of metals used in the weld through spectroscopy. We used metallography to support what we thought the metal was made of and to look for any weaker points in the metal. We found the different sections of the weld by doing this, but didn’t find many signs of weak spots or any outstanding reasons for breaking. We tried a hardness test to find if different parts of the weld were softer. We found little useable data in our results. Toward the end of the week we still didn't have a solid answer for as to why the weld broke the way it did. Finally we went back to look at our first pictures of the welds. We looked up how a weld was done and how it was prepared for a bend test. We noticed that the answer was simple and didn’t even have much to do with how our sample was welded. The weld was simply prepared improperly for the bend test.

Finally we had our answer and next came an even bigger challenge. We had to share our entire week's worth of research in a five slide presentation. After picking the most important things and lots of rearranging, we finally had a good presentation. We left our work room nervously to go to dinner. We knew we would be presenting after dinner, and not only to the other students, but to all of our parents, all of the mentors, a few ASM board members, and even the president of ASM. After dinner we were even more stressed to present, but when they called our group up we were prepared. After our presentation everyone happily applauded us for having done so much in only a week. I felt so proud to have given a professional presentation to several professional people, and to have them accept what we found.

Although our main project took up most of our time it wasn't all we worked on. We also had many different activities throughout the week. We did metal castings with pewter, and later sand castings with aluminum. We used liquid nitrogen to make ice cream and blow up bottles. We even got to try blacksmithing. We had a pool party one evening, and a few people played pool each night.

My favorite part of the week was getting to meet all the people there. In school I’m used to being in groups and being the only one who did any work, but it was the opposite here. Everyone in my group put in a great deal of effort and worked hard. People also came from all over the U.S. and even from another country. My roommate was from california and another student was all the way from Germany. The mentors were from several different places too too. Everyone there was extremely friendly and helpful. Everyone got along well and helped each other. I made many new friends who I know I will never forget.

The Eisman Material Science Camp was an amazing experience and I’m extremely happy to have been a part of it. I’m thankful that Mr. Dusch recommended me to apply to it. I learned a great deal while I was at the camp, and now have experience working in a real laboratory. I may even try to return as a mentor in the future.

Big thanks to Lucas (for the story and for the kind words). Check out some photos of Lucas (no, I won't tell you which one he is, sorry) and the rest of the campers thanks to ASM's Facebook page over at the album I gathered and posted.