That Fresh, Clean Feeling

I’ve decided to do my seminar this semester on the chemistry of hair care. You know, I’m going to talk about all that junk on the back of shampoo bottles that you never really cared to know about– DMDM hydantoin, cocamidopropyl betaine, PPG-9, etc. I’m aiming for practicality here.

Many shampoo ingredients have some fascinating properties. DMDM hydantoin, for example, is a biocide and preservative that works by releasing formaldehyde. “Formaldehyde? In my freakin’ shampoo?” you may ask? To which I would reply, “only in dilute quantities my friend, and it reacts right away outside your body.” W.B. Neely discovered way back in the decade of love that dilute formaldehyde interferes with the growth and division of Aerobacter bacteria by interrupting the biosynthesis of methionine.

Interesting, no?



  1. I think it’s a great topic for a couple of reasons. First, since other people have to sit through your seminar, it never hurts to have something to talk about that everyone has some familiarity with. Well, most people.

    Second, and this even escapes a lot of chemists- designing chemical systems to do everyday things is complicated. There is a huge variety of ingredients in shampoo, as you noted. All of them have to do something worthwhile, and they can’t interact (unless, of course, that’s precisely why they are included). If you can explain why these things are done, everybody will come away with something.

    I remember attending a one-day short course that Procter and Gamble gave on analytical chemistry. They had some mysterious problems with a shampoo ingredient that had suddenly gone from straw yellow to purple. It turned out that they were heating it to reduce the viscosity so it could be pumped more quickly, and then later running it through heat exchangers. At the elevated temperature, the fatty acids pulled Mn out of the heat exchangers. The cost of having that one particular line shut down was something like $60,000 an hour, and it was no small feat to figure out where in the process things went bad. So there are lots of angles you could use to get people’s attention.


  2. A year ago I made a short lecture about capsicum. It had a blowing panda, a talking parrot, the capsaicin molecule and a funny picture of Scoville in the slides. Sadly, I didn’t put Habanero-tan inside because it’s too immodest for my class. :-/


  3. All of hair care chemistry in 20 minutes? And for an industry that has immense proprietary secrets and marketing hype too. “For my next project, I’ll climb Mount Everest. With no oxygen. Backwards. Blindfolded. In just my underwear.”


  4. With only 20 minutes you will have to do even more winnowing than you would for an hour talk. Still, if you can pick a piece of the pie that you find interesting (maybe a single surfactant, or polyols, or something) and make some arguments about what is being done, you could get something good.

    John makes a good point. The really neato stuff is secret. But there’s plenty left, I’d think, and since most people are going to be butt ignorant of the topic, most anything you tell them will be news.


  5. The way I’m organizing things now, I’m dividing up ingredients based on their function (surfactants, biocides, pearlescents, etc.) and explaining how each class works. One slide per class is a little skimpy, but I think I’ll be able to fit it all in.


  6. Ah, you’ll be fine. Grading in undergrad seminar is way lenient. As in, if you do the stupid lit search assignment and the other stuff, and you stand up and give a seminar at all, you have an A.*

    *Even if you talk fast when you’re nervous and run about six or seven minutes short…


  7. Ummmm…no?
    I’m a horrible speaker unless it’s a very informal occasion. Speaking during group meetings is tolerable because I get to make fun of my boss, which takes the edge off being in front of people. (He’s surprisingly good-natured about it.)


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s