Sex, Blogs, and Videotapes

Most any lengthy composition has a sequence, including things as disparate as polymers, novels, films, or even a blog. All these different things are sequentially pieced together from smaller subunits. For polymers, the subunits are monomers, for novels they are alphabet characters, for films and videotapes, they are "frames," and for blogs, they are separate posts (which themselves comprise a smaller sequence of characters).

It might be fun to explore the mechanics of stringing together novels, films, and blogs, etc. For polymers, I already mentioned "step growth polymerization" back here, describing how Wallace Carothers mastered the art of making long-chain synthetic polymers like nylon and neoprene. One way for a non-chemist to visualize step-growth polymerization is to imagine a very large group of unattached people, each willing to reach out and join hands with another to begin forming a human chain. Imagine how this must work at the beginning of the process. All are separate. In a first step, two people get together, each joining just one hand to make a pair, but each leaving one hand free. Now that pair could get together with another like pair to make a chain of four, but it's unlikely to do so because in a sea of singletons it's far more likely that the first pair will just hook up with another single person to make a trio. Again, that's not a choice thing -- it's a statistical thing because the number of available singletons far exceeds the number of available pairs -- at first. Look at the chain growth profile labeled "step-growth" in this chart (the red curve): 

For step-growth polymerization, not until the very end of the coupling orgy do the relative amounts of already linked members far outnumber the available remaining singletons and the daisy-chaining really takes off because having consumed all the singletons, the short chains must join hands with the ends of other chains. In the graph, the step-growth mechanism is contrasted with the living chain growth mechanism (straight line) which grows steadily. An example of the living growth chain mechanism is the Zeigler-Natta mechanism mentioned back here. Comment threads on blogs are also like "living" polymers.

Taking a closer look at the handholding analogy, it's a sanitized whitewash of what's really going on. The monomers in nylon are really "gendered" i.e. there are two types of monomers being joined: there is a "male" monomer, 1,6-diaminohexane which looks like this:

and a female monomer, 1,6-dicarboxyhexane (also called adipic acid) which looks like this:

I've already called attention to the "male" nature of amines, and the "female" nature of acids here. If that analogy bothers you, think instead of plugs and sockets or hands and gloves.

A Tale of Two Picket Fences

Wallace Carothers, American chemist and inventor extraordinaire, had a brief teaching and research appointment at Harvard before leaving to make history at DuPont.  I wrote about him here.  Carothers' mentor at Harvard was Professor E. P. Kohler, a veteran teacher by the time Carothers got there in 1926.  A contemporary of Carothers remembers Kohler:

But after I met him [Kohler]..we sat around listening, waiting for the words of wisdom. He was a bachelor, and he had an old New England house down in some town south of Boston. He had a picket fence around his house, and he talked at great length about what a great thing it was to paint a picket fence. He got enormous joy and satisfaction out of this, and I thought it was awfully stupid. Finally he said, 'The reason this is so wonderful: it's the only thing that I do that has a beginning, has an end, and at anytime I know exactly where I stand.' Twenty years later it finally dawned on me that I'd heard some words of wisdom.' Kohler, now 62, was in his sixteenth year at Harvard when James Conant and Roger Adams presented to Kohler--'the King' he was called--the convincing case for Wallace Carothers as a new Harvard instructor. 

Enough for One Lifetime by Matthew E. Hermes.

Carothers lasted just three semesters before leaving Harvard for DuPont in 1927.  The rest is history. I bring up the story because Professor Kohler's peculiar (and real-life) attitude about fence painting contrasts so starkly with that of the fictional Tom Sawyer, forever captured by Mark Twain:

Tom appeared on the sidewalk with a bucket of whitewash and a long-handled brush. He surveyed the fence, and all gladness left him and a deep melancholy settled down upon his spirit. Thirty yards of board fence nine feet high. Life to him seemed hollow, and existence but a burden. Sighing, he dipped his brush and passed it along the topmost plank; repeated the operation; did it again; compared the insignificant whitewashed streak with the far-reaching continent of unwhitewashed fence, and sat down on a tree-box discouraged.

Of course the guileful Tom goes on to convince his friends to paint the fence for him, and that of course is part of his charm.

What sort of character do we reward in workers and leaders today?  Which traits do we admire in ourselves when faced with such a task?

Blessed Are The Wealth Makers

Wallace Hume Carothers (1896-1937)

DuPont made a fortune selling things like gunpowder and nitrocellulose to warring governments (mainly to our own) up through and including the First World War. During the roaring 1920s (and flush with cash before the crash) they decided to pursue pure research into material science and established a new division at their fledgling Experimental Station located near Wilmington, Delaware.

The company hired a young PhD chemist named Wallace Carothers to start up a new group. Carothers was fascinated by long chain macromolecules ubiquitous in nature but which had only recently been recognized as "polymers." With the exception of Bakelite, the first synthetic plastic,* other synthetic polymers were unheard of, let alone commercially successful.

DuPont's research gamble paid off and Carothers and his group brought the company enormous success, first with the serendipitous discovery of neoprene, the first synthetic rubber, and then with nylon. Neoprene and nylon were tangible wealth creation: making things of value from what were, at the time, essentially waste products.

Nylon was Carothers' baby. Not only did he invent a synthetic replacement for silk, he purposefully developed a new method of making polymers called step-growth polymerization. He used the same durable type of linkages used by proteins (amide bonds), mimicking nature. Nylon was the first synthetic fabric and was commercialized around 1938, just in time to replace Asian silk which, along with natural rubber, went missing during the Second World War.

We have a lot to thank Carothers for but he didn't stick around. He checked out early, killing himself in 1937.
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* I have two items made from Bakelite: One is a late 1940's era Viewmaster device and the other is my father's old Kit-Cat clock which I described here. Both of these items have the characteristic fragility and tendency to chip common to Bakelite.