Friday, December 30, 2011

Mt. Stupid

From Saturday Morning Breakfast Cartoon on December 28, 2011 (Note that this particular comic is safe for work, but that is not always the case with SMBC):
Here's hoping that 2012 finds us all climbing the ultimate steep slope on the right hand side and never interacting with anyone living on Mount Stupid.

And with that, I'll be taking a few days off of well-earned vacation now that our corporate move is winding down.

Thursday, December 29, 2011

A Bullet to the Head

There was a report earlier this year of a Chinese man that had had bullet lodged in his brain for 23 years, but now the New England Journal of Medicine has a report that trumps that - a Russian man with a bullet lodge in his brain for 82 years! Take a look:
According to the doctors,
"The patient revealed that at the age of 3 he had been accidentally shot with a pistol by his older brother. The bullet had struck him just inferior to the nose, and he had lost consciousness for several hours, recovering completely without specific therapy. In his adult life, he had achieved professional success as an engineer, even winning the Soviet State Prize for his accomplishments."
82 years is a record unlikely to be broken. Isn't it strange that he was shot and that no medical evaluation was even made at that time?

PEO Crystals - The Snowflakes of Polymers

While polymer single crystals have always showed a myriad of shapes, articles on the crystallization of polyethylene oxide (PEO) has always been the most exciting to read. That polymer, more than any other is able to crystallize into a seemingly endless variety of forms depending on reaction conditions. This is largely because of the flexibility of the ether linkages in the backbone. There is minimal hindrance to axial rotations and so getting some type of crystal to form is pretty much a given. It's just that no two crystals seem to be the same, much like snowflakes. Consider these 8 examples:

The above AFM photograph comes from a research letter (open access) published in the new ACS journal Macro Letters. As with all crystallization, you have the competing effects of nucleation and growth occurring. The relative rates determine the shape of the final crystal. Working through a wide range of supercooling conditions and molecular weights, the researchers were able to create a "morphology" diagram - a map of what conditions will lead to what outcomes. Here's a look at it:
where the letters in this figure corresponds to the different morphs in the previous diagram. The general trends is that as the supercooling (or molecular weight) increases, the fiberous nature of the crystals increases as well.

It's a short article with lots more detail in it - I highly recommend reading it if you have an interest in polymer crystallization.

ResearchBlogging.orgZhang, G., Zhai, X., Ma, Z., Jin, L., Zheng, P., Wang, W., Cheng, S., & Lotz, B. (2011). Morphology Diagram of Single-Layer Crystal Patterns in Supercooled Poly(ethylene oxide) Ultrathin Films: Understanding Macromolecular Effect of Crystal Pattern Formation and Selection ACS Macro Letters, 217-221 DOI: 10.1021/mz2001109

Wednesday, December 28, 2011

Chemistry vs. Physics &. Biology

Of the three physical sciences listed above, physics and biology seem to have a lot in common, with chemistry being the odd-man out.
  • Physics and biology both have "dissident" scientists who disagree with some of the key fundamentals in the science. You don't have to spend too much time in physics forums to run across people who think that all of quantum mechanics and/or relativity is wrong, and that they have a better explanation that doesn't require ideas that clash with our everyday experiences. Biologists have to deal with all the people, including scientists, who deny evolution. Fortunately, chemistry seems to be immune to "dissident" thought. I can't think of a single example where a fundamental chemical idea is challenged.
  • Physics and biology have both done a better job of selling themselves to the general public than chemistry has. Physicists are able to get funding for particle accelerators that may not ever be able to produce results applicable to the "real world", and yet many in the general public are well aware of the search for the Higgs Boson. Astrophysicists are similarly able to get funding for ever larger telescopes and space telescopes. As long as they produce the occasional breathtaking picture of nebula and galaxies, the general public is happy. As for biologists, they were able to get billions for sequencing the human genome, although they at least held out the promise of "personalized medicine" and the discovery of the gene that causes disease X, Y and Z (with the soon to follow cure for these diseases). Has there ever been a large scale chemistry project, let alone one that captured the public's imagination? I can't think of any.
  • Chemistry seems to more feared by the public than physics or biology is. I'll admit that this is a personal perception that might be heavily tainted by my experiences, but it seems to me that there is more chemophobia than there is fear of anything that physicists or biologist work with. Certainly there is fear of radiation and certain microbiological organisms, but these fears are limited to rather thin facets of life - nuclear power plants & weapons for physics, and food safety & infections/disease for biologists, whereas chemophobia can exist with practically everything that people touch in their lives. If a physicist is working with optics, that's o.k. If a biologist is working with fish, that's o.k. [*] If a chemist is working at all, it's with chemicals and that's bad no matter what.
While I am glad that we don't have to deal with the crackpots, it sure would be nice to have a few large-scale projects that the public is all to happy to pay for, one that will improve their perception of chemistry and reduce the amount of chemophobia in the world today.

[*]as long as they are not genetically modified fish. (I realize this is a small concern in the US and a bigger concern in Europe.)

Tuesday, December 27, 2011

The Two Sides of Plastic Man

Throughout history, "Plastic Man" has taken many forms. The oldest version is the comic book graphic novel hero. Being plastic, he was able to assume a vast array of shapes such as
or even this
All this fame and glory earned him a spot on US postal stamps back in 2006:
and apparently even had his own Saturday morning cartoon show in 1979
(I never saw it - at that point I was too deep into upperclassman chemical engineering classes to watch TV.)

But,like all Superheroes, "Plastic Man" had his dark side, as can be seen in this video from Sonny [*] and Cher from 1968:

The Kinks also had their own song "Plastic Man" the following year with entirely different music and lyrics (that Heaven for small favors), but equally disparaging: 
From Superhero to Superzero - the life of Plastic Man

[*] This man went on to be come the Mayor of Palm Springs and then later, a US Congressman, believe it or not.

Wednesday, December 21, 2011

Aspen Research has Left the Building

Yesterday the last truck arrived with all the goodies from our old building. We are now officially moved and located at our lovely new building, 8401 Jefferson Highway in Maple Grove, Minnesota. Having left the city of White Bear Lake, we no longer have to explain that we are so far north that we have white bears. "Maple Grove" is just another generic suburban name that needs no explanation (Wikipedia lists over a dozen cities in the US and Canada with the name. I've never seen a disambigulation page listing further diambigulations, have you?) Now it's just a matter of hooking everything back up, reclaiming the chair and desks and file cabinets and ... that others are squatting on, and away we go. The computer network is fine (YES!), the offices are nicely finished (the nicest cubicles I've ever seen) and significantly bigger than what we had before. How small were our old cubicles you say? Let's just say that Aspen Research was a leading the charge on nanotechnology 20 years ago.

With the whole operation of unpacking everything and putting it all in new places, you do get to look at all the stuff anew and rediscover some things, decide other things are no longer worth keeping and yet other items are going to be dealt with differently than before. It's all good.

Tuesday, December 20, 2011

Not Hiring Someone You Should Have

When a decision is being made to hire a new employee, I see 4 potential outcomes based on two factors. The first is obviously whether or not to hire the person, and the other is whether or not the person should be hired. A simple diagram of this situation is this:
The people in the upper left hand corner we all know about - the ones who got hired and are working out well, and the same goes for the lower left corner - the ones who got hired and are not working out well [*]. The right hand side of the chart however, is more of a mystery. When a decision made to not hire someone, there is no feedback. Very seldom do you ever find out if you made the correct decision or not.

This discussion however, was all made on the basis of a single person making the decision or equivalently, an entire team being in agreement on the decision. If that is not the case, then it is possible for some people to explore more of the right hand side of the box. I can recall one case where I recommended against hiring an individual, the manager did it anyway and it turned out to be the correct move. Through that, I was able to explore some of the upper right hand corner, although it was just me and not my manager. While it is good, that's one of those situations that can really haunt you, that you would have let someone good get away. I never have claimed to have great insight on hiring, and that case certainly proved it.

[*] It's been my experience that large corporations have a very difficult time getting rid of these people, which is why I called that box a "really bad decision". Even if the person is ultimately let go or leaves on their own, it still is wasted time and effort for all involved.

Monday, December 19, 2011

The Supreme Leader's Contributions to Polymer Science & Engineering

With the passing of North Korea's Supreme Leader Kim Jong Il, I thought that we should review the many contributions that the master of all trades gave to the field of polymer science. After all, anyone who can shoot 38-under par (including 5 aces) in his first time on a golf course, write 6 operas in two years and personally design the Juche Tower
certainly must have made immense contributions to polymer science.

Sure enough, he did. A quick search for with the terms "Kim Jong Il" and "plastics" yields a treasure trove of results, although you first have to get past all the articles about his son having plastic surgery so as to look more like his grandfather. But here's some paydirt - the Supreme Leader in an undated photo touring a plastics factory:
A press release from just a few months ago further elaborates the man's involvement with the Raknang Plastic Goods Factory:
"He set forth the tasks to be implemented by the factory.

An important duty facing the factory is to produce more plastic goods conducive to improving the standard of people's living in reliance on the existing production foundation and bring their quality to the highest level, he said, and went on:

It is necessary to direct great efforts to the technical control and the management of equipment and, at the same time, steadily raise the level of technical skill of the producers.

When making a product, it is essential to produce goods liked by people, products impeccable on any market and having world competitive power and increase their varieties to meet different demands and taste of customers."
Extremely insightful, wouldn't you say? We can all learn from this great man. I am sure as well that he was able to provide pointers for removing mold lines and addressing the blush issues that keep creeping up from time to time (such as increasing the cooling water temperature by 10 degrees).

But was this man limited to just knowledge of injection molding? Of course not - he was skilled in extrusion and fiber spinning too: Back in February, he toured a factory making vinalon, a fabric made from polyvinyl alcohol,
and the press reported:
"He expressed great satisfaction over the fact that the workers of the complex and their helpers have successfully wound up in a short span of time the huge project equivalent to the construction of a large chemical base by their own efforts and with their own technology in hearty response to the intention of the Party to develop the economy their own way and improve the people's standard of living by depending on the nation's economic foundation.

It is an astonishing miracle that the builders have constructed a precious structure of eternal value by their own efforts under so hard conditions by valiantly overcoming bottlenecks and difficulties lying in their way and dedicating their all to the project, he said. He extended high appreciation and thanks to them for having performed the laudable feats for the country and people."
(emphasis added).

Do you see that? Eternal value! Those of us outside of North Korea build machines that will last for a few decades at most before being discarded, but Kim Jong Il was able to devise machinery that would last forever. Truly this was the Supreme Leader. His only shortcoming was having a human body.

Friday, December 16, 2011

The Real Danger in Polycarbonate (it's not BPA!) and a Solution for it

Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will kill you. But for PC, that is only half the story.

Polycarbonate is normally made by copolymerizing BPA and phosgene. Phosgene is the real bad guy that needs to be feared with all your being. Phosgene has a long track record of killing people, beginning in World War I when it was used as a chemical weapon, and it's potential use was feared in World War II [*]
While industrial accidents with phosgene have been relatively rare, they do occur. Some recent examples are a leak that led to the death of a DuPont worker last year in West Virginia, and leaks in Thailand and China that in both cases also had a death, along with hundreds of injuries. BPA never did this to anyone.

But not content to continue living with these problems, that creative bunch of people known as polymer chemists (Ouch! Sorry, I twisted my arm patting myself on the back) have devised phosgene-free routes to prepare PC, typically using diphenylcarbonate (DPC) as a replacement for the phosgene. BPA is still in the picture, but the DPC is a much safer option than phosgene. Shell Chemical has been a large driver in this effort and is building a pilot plant in Singapore to supply this material. The DPC is made in part with carbon monoxide which is nowhere near as toxic as phosgene.

It's also interesting to note that despite the economic downturn and all the people avoiding PC like an elephants avoiding mice, PC production is still growing at 4 - 5% a year.

[*] Phosgene is a great example of something being quite deadly but not having a wretched smell.

Wednesday, December 14, 2011

Isolating Thixotropy from Shear Thinning

With non-Newtonian fluids, the viscosity is no longer constant. Depending on the flow conditions (and the material of course), the viscosity will decrease as the shear rate increases (shear thinning) or it will increase (shear thickening). In some cases as well, there is a time dependency - the viscosity at a given flow condition can decrease over time (thixotropy) or increase (rheopexy).

What I've just describer however, are ideal models that don't exist in reality. As far as I am aware, a purely shear-thinning material does not exist. Sure, most thermoplastics do show shear-thinning behavior, but it is over a range of shear rates, rather than ALL shear rates. (At low shear rates, the viscosity becomes constant and is given the name of zero-shear viscosity, and a some materials will also show a constant, high shear rate viscosity). The same is true for shear thickening materials - such behavior is observed over a range of shear rates and not in other subranges. And it becomes a bigger mess when time-dependent behavior is added. I've never seen a thixotropic material that wasn't also shear-thinning.

It would be a great help for educational purposes if we could find such materials that show only these isolated ideals of non-Newtonian behavior, particularly with the time dependent phenomenon. I think all educators have students that struggle with the difference between shear-thinning and thixotropy. A material showing only thixotropic behavior would be a great aid in demonstrating the difference.

Lastly, there is one set of fluids I am aware of that are able to isolate one subset of non-Newtonian behavior and those are Boger fluids - they have a constant viscosity like a Newtonian liquid, but show large amounts of elasticity.

Tuesday, December 13, 2011

A Derivation of the Cox-Merz Rule

For reasons I've never understood, the most common search term that consistently, year-in, year-out brings people to this blog is "Cox-Merz rule" or some variation thereof. So I'm going to add fuel to the fire with some new research results about this important rheological relationship.

The Cox-Merz rule is a empirical observation that h( \dot \gamma ) = h*(w) when  \dot \gamma = w.

The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. Sharp observers will question how a sinusoidal deformation can be useful in a production setting which has unidirectional flow (or something close to it). The Cox-Merz rule is able to jump that gap - as long as the magnitude of the oscillatory frequency matches the magnitude of the steady-state shear rate, then the viscosities will be the same. This was first observed empirically and holds for many many materials, thus greatly simplifying the equipment and time spent in the lab.

But once one learns of the rule, the questions then arise as to when it won't work. Again, empirical observations have shown to be cautious with "networky" type materials such as filled polymers or systems with complex hydrogen bonding for example.

David Mead has a fine magnum opus published in Rheologica Acta (free access until the end of the year!) in which he is able to derive the Cox-Merz rule for polydisperse materials. This has been previous done for the idealistic case of monodisperse polymers, so this is a real advancement. The kicker however, is the last line in the article (actually, the last line in the Appendix):
"The Cox-Merz rule is effectively a 'suspicious' coincidence' based on identical dimensionless frequency transitions and correct asymptotic scaling behavior rather than anything predicated on fundamental polymer physics."
All this work and our basics thoughts aren't changed.

Mead, D. (2011). Analytic derivation of the Cox–Merz rule using the MLD “toy” model for polydisperse linear polymers Rheologica Acta, 50 (9-10), 837-866 DOI: 10.1007/s00397-011-0550-5

Monday, December 12, 2011

The Future is Clear

Two new research articles were recently published, both of which have a common theme: taking objects that are normally opaque and (through the magic of chemistry) making them translucent. Both materials are made up a (more or less) continuous matrix which enclose open spaces. However, the approaches to translucency differ and make this an interesting comparison.

The first object to become clear is a crab shell (original article ($), review (free)), which involves immersing a (dead) crab into a serious of baths - HCl, NaOH and ethanol to remove the minerals, proteins, fats and pigments and leaving just the chitin behind. The chitin is then "clarified" after acrylic monomers are injected and reacted. Here's a picture from the abstract of the starting material, after the three baths, and then the final product.
The "clarification" that occurs in the last step occurs is the removal of scattering sites because the refractive index of the acrylic and the chitin are similar. Absent the acrylic, the air that filled the opening left by after the other materials were washed out in the baths was different enough in refractive index to cause scattering.

The second object that is clarified is an open-celled glassy, foam (original article ($), review article (free)). The preparation technique is completely different - a polyurethane sponge is used as a template, into which nanoparticles of silica are added, the pH is adjusted, and then the urethane is burned out leaving the clear glass foam behind. Nanoparticles are generally too small to scatter light, so even with the difference in refractive index between the silica and the air, clarity is maintained.

I'm not sure if this is the start of a trend that we will see more of, but it might very well be since transparency is generally considered "good" and increase visibility (and not just in science as transparency in government and financial institutions are both highly desired). A rheologist that I knew from an earlier portion of my career had replaced the covers on the twin towers of his Rheometrics RDA rheometer with acrylic so that all the electronics inside could be visible. It was quite a bit more interesting to look at than the normal beige - I'm just not sure that any real purpose was served.

Wednesday, December 07, 2011

Still Moving

Posting has been slow, especially compared to the number of boxes I've been filling this week.

For those who missed the post last week, Aspen Research is on the move to a new, bigger-and-better location. But is all comes at a price. Mr. Client, we won't be running your sample this week.

In the process, we've all learned a few things.
  • Nothing gets chemists to stop bench work and start packing like shutting down their hoods.
  • A hydraulic lift table
    is fabulous for sliding heavy lab equipment off the bench and then onto a pallet. Don't move without one.
  • I need to go through all the papers I've collected over the years and toss some of them. At the same time, some of them definitely need to be reread (and blogged about).
  • Everybody is all wrong about zombies. When they are wandering about, they are NOT looking for "Brains!", but internet connectivity. When we lose ours on Friday PM, you're going to see 42 lost people wandering around with their computers looking for "Internets!" If we were to become zombies, why would you expect us to behave any different?
After a week of this effort, we are making headway. Stuff is disappearing from the staging areas and into trucks faster than it is being replaced. People are starting to straddle between the two buildings. Off we go.

Friday, December 02, 2011

The Teacher Can Make All the Difference

Quite a few years ago, I worked for a large corporation that had a high school "internship" program (for lack of a better word). The program was limited to students from the larger core city, not the suburbs (so it was a community outreach program as well). The program consisted of a weekly set of 2-hour "lectures" from January until June, followed by employment during the summer in various labs around the company. The lectures were taught by company employees about a wide range of technical subjects. I gave two talks about polymers and enjoyed it tremendously as it was a great bunch of kids to be working with.

I realized before starting this effort however, that I had to make it interesting, which meant only enough math and theory to clarify concepts, and lots and lots of time in the lab playing with all the craziest non-Newtonian materials I could devise. I had examples of rheopexy (cornstarch/water), the Wissenberg effect (rod climbing), Slime (PVOH/borax/water), Pluronic gels that thickened up heating and liquified upon cooling...Their homework assignment between the two lectures was to find non-Newtonian materials in their homes which they did reasonably well at [*]. And knowing that if I'm not excited about the subject, they wouldn't be, I put as much energy into the talks as possible, portraying how exciting polymer science can be.

The reviews came back at the end of the semester and my jaw hit the floor. The students thought I had done a great job, in fact they consistently ranked me as the second best teacher. It's just that "the cement guy" was better! CEMENT?!?! I never got a chance to talk to that guy, but if he could make cement even more exciting than polymers, I tip my hat to him, and say "the teacher can make all the difference".

[*] My favorite discussion item for a non-Newtonian material at home is toothpaste - a Bingham fluid, but it has to be discussed "properly". To do so, I would set the scene by getting them to think about being in the bathroom. I would then slowly lower myself into an armless chair, pull out some reading material and talk about a material that you need to apply a certain minimal stress to get it moving. Not enough stress and it would pop back in, but with enough stress, things would move along smoothly. It wouldn't take too long before you would see some smiles and smirks and they finally realized what I was talking about - toothpaste! (What were you thinking?)

Thursday, December 01, 2011

Moving - A Lab's Ultimate Nightmare?

The calendar now says December, a month we have long dreaded here at Aspen Research. Normally we get the year end rush of people trying to get things done before the end of the year while they still have the money in the budget, but this year is entirely different. We are moving across town to a new location.

I've never moved a lab before. When I worked for a megacorporation, my wife's division had to move their lab to another building, but that was move from one lab building to another lab building. Things like hoods and benches were left behind and were already in place at the new location. This is entirely different. We are taking it ALL with us: extruders (and all of their auxillary equipment), benches, hoods, sinks... pretty much everything except for the lingering aromas of the many thiols I work with.

Why the move? Expansion. The new building is twice the size of this one and we will need it all very quickly.

In some ways, the sale of Aspen Research from Andersen Corporation back in February was a practice run, even if very little physically moved. As part of the sale, we needed to divorce ourselves from all the shared IT resources (not just internet and computers, but accounting, HR...), so we've been there and done that fairly recently, and in this day and age, quickly and efficiently moving and reestablishing IT resources is everything. Fortunately email addresses don't change, cell phone numbers don't change and the desk number (which are changing) will be rolled over automatically for a year.

Hopefully Santa Clause will still find us in the new location. There is this capillary rheometer [*] that I really want and I've been a good boy all year...

[*] "...with a compass in the stock and a thing that tells time..." and no, I'm not going to shoot my eye out.