I <3 Your Cover

And… we’re back!

Where has the time gone? Between finishing classes, advancing to candidacy and trying to complete some work for a patent, the past 4 months have been busy. The kind of busy that prohibits you from shaving and causes you to start missing meals.  I really like writing this blog and participating in the chemistry blog community in my own meaningless way, so to get my head back in the game I present to you some fun things I’ve seen around the lab lately. Someone needs to represent for polymer chemistry and unfortunately for it that person is me.

The power aspirator will work better if I turn the water up all the way right?

 

This seems like a perfectly reasonable place to park a bike. If the antechamber were a little larger I'm sure the bike would be inside the box.

Your long overdue column of the "month."

My therapist says that this is good for me, so I’ll be talking to you shortly.

Reasons why Google is tight.

1. Robert Bunsen themed home page! Thank you Google.

Let the spam bots try to read this!

I know you’re famous but really?

Good thing we did that! Otherwise someone might accuse us of being chemists.

OK, what the hell is up with this!!! This makes me so mad I am struggling not to have a seizure. What was the point of anesthetizing a mouse and picking it up? “Oh look we picked up a mouse and we didn’t even fuck it up!” What a totally irresponsible and stupid use of a research animal. If you wanted a delicate task you could’ve fondled my balls!!!

In case you missed it in C&EN or somewhere else on the internet George Whitesides and his army of post-docs have made a soft robot that can pick up an egg or an anesthetized mouse. It’s kind of clever. They layered together PDMS (a relatively rigid elastomer) and EcoFlex (a really soft elastomer) to make a composite with pneumatic channels in it. By pressurizing these channels they could make the composite move and grip things. Pretty clever.

But what the hell is it doing in Angewandte Chemie? I mean really, this is an engineering/robotics article and has NO place in a chemistry journal. I didn’t see one chemical scheme, NMR spectrum, X-ray structure or DFT calculation. Nothing! All I saw was a nifty little engineering project in a chemistry journal because we all know who the author is.

Next problem. Why did you need to anesthetize that mouse? What extra special knowledge did you learn from tranquilizing that animal and picking it up? Did you have any idea if that was going to crush the mouse, or did you try a couple times before you didn’t smash one? For Pete sake, you didn’t even show that the mouse wasn’t hurt with an X-ray or something.  Come on you guys are better than this and are giving a bad name to the people who are genuinely trying to be responsible with research animals.

Black Magic and the Chinese New Year

Me publiz first autor in JACS

Last Wednesday because of the world ending snow storm that engulfed the entire eastern United States and the Chinese New Year I found myself almost totally alone at work. My university closed, what ever that means, and the only other being insight was Mittens my research kitten. I walked into the NMR lab without scheduling any time and used the instrument for 90 minutes in the middle of the day. It was probably the coolest thing to happen to me this year. And as I sat struggling to shim my sample (no I don’t use one of the instruments that shims itself my adviser thinks its frivolous) I remembered something that has been repeated to me by every NMR instructor, lecturer, handbook and manual that I have ever heard or read, “shimming is more of an art than a science.” And perhaps it was the clarity offered by isolation or the frustration from using economy tubes I lightly warped in the drying oven, but I realized SHIMMING IS NOT AN ART!

Art? What does that even mean? If it’s meant to imply that there is some amount of finesse and intuition involved in shimming I agree, but this is also true of billiards and sausage making. Art is something that has complex meaning and depth of emotion. Shimming is more like a puzzle or a craft. Tricky in its own right, but it is what it is. So spectroscopists stop patting yourself on the back and have a dumpling.

Happy New Semester

As the new semester rears its ugly head, reducing available parking space and crowding the elevator (who rides the elevator to the second floor?), I will resume semi-regular posts. I spent the winter “break” meditating on the future of polymer chemistry, while keeping vigil at Hermann Staudingers  mausoleum. Unfortunately for you, I never figured out what that future is and I don’t like posting useless snippets (other than this one of course), so I have refrained from posting over the break. However, I should be back in the swing of things in no time, plus I owe you a CoMy.

Talk to you soon,

AGAM

Renew… or else!

I arrived home yesterday to find a package stuffed in my mailbox. I couldn’t have been more excited. Was this an early Christmas present? Perhaps the socks I so desperately need.

Yes, I live in a castle.

Joyous rapture, it was my American Chemical Society 1 year anniversary mug. Finally, I could drink coffee on my coffee break. I should have joined ACS more than a year ago, but it never seemed pressing until I was registering for a regional meeting this time last year.

I can hardly sleep at night.

Great Gatsby, MY MUG!!!…ACS I know you are reading this. My membership renewal is in the mail.

Column of the Month (12/10)

I’ve been collecting pictures of “pretty” columns I ran, so I thought I’d share them with you on a weekly* monthly basis. Maybe I can turn it into a calendar when all is said and done. Most of my columns are colorful, but I don’t run that many, because polymer chemists are ham-fisted when it comes to chromatography. (If the difference in Rf is less than 0.75 forget about it.)

So, to keep this up I’ll need some help. If you have any pictures of attractive or interesting columns that you ran please send them to me at agiantamongmolecules@gmail.com and if they are chosen to be “column of the week month” I’ll send you a prize.

Without further ado here is your CoW CoMy.

I call this the tequila sunrise.

* Let’s be honest. I don’t run nearly enough columns to do this on a weekly basis.

I feel so misunderstood

SPECTROMETERS! Can't live with them. Can't live without them.

All scientists will eventually misinterpret something and waste a bunch of time chasing a ghost. You might catch it fast, saving yourself the trouble of needless purification and looking foolish, or you might not catch it until someone with better hands tries to replicate your results. It took me about a week.

I’ve been trying to make (have made) a homo bifunctional poly(ethylene gylcol). There are well established procedures for attaching all sorts of functionality to PEG chain-ends, so it really shouldn’t be a big deal. (It wasn’t.) Unfortunately for me, I am a fool and chain-end functional PEG has the following pitfalls, which I fell into.

1. With chain-ends not visible by 1H NMR spectroscopy, say azides or normal hydroxyl chain-end PEG, all you can see are the methylenes α and β to the chain-end. This would be fine, except they really aren’t that different from the backbone methylenes and so don’t shift much relative to the backbone resonances. So, it’s hard to see how the reaction went and how clean your product is. I thought my product was dirty.
2. Observing the chain-ends using 1H NMR spectroscopy is a little difficult because there just aren’t that many of them compared to the backbone. So, your chain-end signal is weak. Combined with PEGs similar chemical shift problem, see above, the backbone resonances sometimes drowned out the chain-ends. Or because I use wonky old NMR tubes and shim like a five year old uses a coloring book, spinning side bands of the overwhelmingly strong backbone resonances start to look like unreacted reactants. This made me think my reaction would not go to completion.
3. If you try to separate a mixture of di-, mono- and non-functional PEG on a column, the chromatography gods will laugh at you. First of all, the difference in affinity for the column created by the different chain-ends is counter-balanced by the similar backbone. It’s mostly just PEG repeat units. Secondly, in addition to having a distribution of functionality (di-, mono- and non-functional) you also have a molecular weight distribution complicating things. In my experience this combination results in streaking and very poor separation. You just end up collecting a mixture of products for ten hours and then smashing your column in frustration.

Luckily the above problems are imaginary for the following reasons.

1. If you use reactions that are quantitative, and use the low molecular weight stuff in excess, you are going to get quantitative functionalization. Send it off for MALDI-TOF and relax. It probably worked fine.
2. If you are having trouble observing chain-ends, up the concentration, up the field and up the number of transients. You can observed chain-ends up to pretty high molecular weight, much greater than 10kDa anyway. It wouldn’t hurt to buy some new NMR tubes, too.
3. Forget, forget, forget about a column! If you assume the reaction is quantitative, see above. Then all you have to separate is low molecular weight stuff. This is where the polymer purification flow chart comes in handy.

All you need to know.

Happy Thanksgiving

I’m thankful for the two or three people who read this blog and that someone pays me to make polymer. Have a great Thanksgiving or at least a great day and may all your polymers precipitate.

-AGAM