Who Discovered the First High-Conductivity Organic Polymer ?

"For the discovery and development of conductive polymers" Nobel Citation .

A Nobel imprimatur defines the history of discovery, rightly or wrongly. There are two issues. 1) the first high conductivity organic polymer. 2) The first organic electronic device.

First, we did not report the first high conductivity organic polymer. In addition to the special case of charge-transfer polymers, this is apparently Bolto et al's report on high conductivity in iodine-doped oxidized polypyrrole (Australian Journal of Chemistry, 1963 16: 1056-89). PDF version Here. However, we can find not a reference to an active organic electronic edvice before our 1974 Science paper. If anyone knows better, please inform us. Thus, our gadget is now in the Smithsonian Chips collection of the American Museum of History. Likewise, the active element in nearly all such subsequent devices is also technically "melanin", a synonym for polyacetylene and its derivatives. For a summary see this Review from IBM.

Bolto et als 1963 paper appears to be a direct analog of the Nobel winner's 1977 paper, except that it substitutes polypyrrole for polyacetylene. However, was our device equivalent to Shirakawa, Heeger, and MacDiarmid's Nobel-prize-winning later discovery of another high-conductivity form of polyacetylene ? It depends on how you define this. Again, melanin is a polyacetylene and vice versa. Thus, an older name for such compounds is acetylene, aniline, etc., "blacks". Similarly, both parties explained conduction in our compounds the same way--- phonon-assisted hopping, mobility gaps, etc.. That is, the science is the same.

So, simply-stated, the basic difference between our work and that of Weiss et al and Shirakawa et al(1) is that they used chemical "doping" (actually, oxidation) to produce a high conductivity state in one melanin, while we used an electric field to produce a similar result in another. That is, we made an active device, a bistable switch. The "on" state of this switch has high, "metallic", conductivity.

This was well-appreciated at the time--- e.g, a Nature "News and Views" article , from April 5, 1974. Here Nature's "Solid State Physics Correspondent" emphasizes our material's " strikingly large conductivity", " highly conducting state " and " large conduction " . This was three years before Shirakawa et al's Nobel-winning report.

So what happened ?

Though the Nobel Foundation spends about 60% of its budget to prevent such errors, they clearly missed this earlier work. For example, the citation implies that Shirakawa et als' 1977 paper (1) was the first demonstration of a highly-conductive organic material. This is clearly incorrect in view of Balto et als report, and (arguably) ours. and likewise, the citation implies that this eventually lead to the first organic electronic devices and that this was the first application of Mott et al's theories on conduction in amorphous materials to such compounds.

So, In addition to the Bolto papers, they missed both John McGinness' 1972 paper in Science explaining electronic conduction in melanin in just such terms and our 1974 report of both such an electronic device and an incidental highly conductive state in melanins.

Similarly, a primary reason given for the Nobel is that the winner's work led to the (re)discovery of active organic devices. Would the Nobel committee have made this award had they known of any prexisting device ?

Science and Nature are the highest impact journals in the world. Obviously, this eliminates a major cause of Nobel "misses" and of citation failures. Likely, in 1974, a conductive organic polymer and an organic electronic device seemed a sui generis oddity. Similarly, the generation of physicists ( such as Neville Mott* ) who knew of it passed. Meanwhile, the field went through the "bottleneck" of the eventual winner's work, which never cited this prior art in over 500 publications.

This lack of citation is puzzling. Did the eventual Nobel winners know about our work or that of Balto et al? And if so, why did they not cite it?

True, "there is always history". But minimally this is convergent discovery, not history.

Thus, our "prior art" includes 1) a high-conductivity form of an organic polymer. 2) an organic electronic device, 3) the now-accepted model for conduction in such materials and 4) patents for batteries describing a rather similar material to that in their patents.

Our device also involved the same chemical class as theirs and most later such devices. Similarly, following their first battery patent, we tried to contact them, but gave up because of no response.

Had anyone acknowledged such communications, this would have indicated "constructive knowledge" of our work, with its attendant patent problems. If there is shenangans here, it likely involves the advice of a patent attorney and not Nobel fever.

Likewise, all three eventual Noble winners were active in this specific area at the time we published our papers in Science. If Nature's "Solid state Physics Correspondent" saw our device paper almost immediately, why did three future Nobel Prize winners (with the enormous scientific competence this implies) not know about it years later?

Perhaps this is "Disregard Syndrome"(2,3) AKA, "Citation Amenesia". This can be quite inadvertant and involve things as simple as a name change. For example, had we as correctly titled our paper " Amorphous Semiconductor Switching in a Polyacetylene ", the connection would have been clearer. Similarly, both parties have patents for much the same thing ( e.g., batteries ) and are cited in a patent for another organic battery.

Many of their later general patent claims are essentially identical with our "prior art". For example, the two McGinness patents ( 4,366,216 and 4,504,557 ) tacitly involve the following items: 1) the reversible reduction and oxidation of a 2) doped, 3) conductive, 4) zwitter-ionic, 5) redox polymer with 6) carboxyl and/or sulfonyl groups in a 7) protic solvent such as water or alcohol.

In a further striking example of convergent discovery, these are also key general claims in later Heeger and MacDiarmid patents and part of the "development" in the Nobel citation. The denial of these general claims because of our prior art would have severely limited the scope of their patents. E.g., the "protic solvent" makes possible practical batteries and greatly extends the range of possible materials and devices. The Bronsted acids, etc. make a polymer "self-doping" ( which melanin is ), etc.

That is, their original Nobel-winning discovery was a dead-end because of its instability and lack of usefulness. By convergent invention, Shirakawa et al eventually ended up with materials and technology rather like ours.

Specific examples include MacDiarmid's EP0131829** ( "Polymer Batteries and Fuel Cells having Protic Solvents and Methods for their construction and use" ) and Heeger's US5569708 ( "Self-Doped polymers" ), as well as many of their other patents. Even some minor details are similar. E.g., we used diethyamine as a dopant, they use methylamine, etc.. Similarly, McGinness et al '557 claims carbonizing a conductive polymer ( "..or formed by graphitization upon heating..." ) as does Shirakwa JP2001172369 ( " Carbonized Polymer Material and its production method " ).

On the other hand, arguably, this just reaffirms that inventors are secondary and that the discovery is the thing. When the time is right ( in this case, following the characterization of conductive mechanisms in disordered materials ), inventions essentially invent themselves.

But this is a distinct issue from a viable scientific cursus honorum. Here, discovery credit plays an important part, however trivial it may be otherwise.

The reader can draw his own conclusions. Personally, we always reasonably believed, perhaps incorrectly, that they knew about our work. The patents are both the motive and the smoking gun. While correct citation is a courtesy in basic science, patent law requires it.

When they did not acknowledge our "prior art", even though it was brought to their attention (a very bad thing in patent law). we figured this was just on "advice of counsel". That is, it was relatively unimportant except if we got into a patent dispute over our essentially-identical materials. So we just dropped the issue.

Imagine our surprise when they won a Nobel prize. Finally, while their relevant patents are still valid, they can never admit they knew about our work.

Ironically, while we played with it, we considered increasing melanin's conductivity by doping of little import compared to a true electronic device. Drawing upon the work of others such as George Cotzias, we had even previously noted that doping of melanin by charge-transfer agents ( including iodide and transition-series matals ) might modulate its conductivity. Some melanins even emit a flash of light as they switch, implying possible electroluminesence.

Peter H Proctor, PhD, MD

*Physics Nobelist Nevel Mott, correctly identified melanins ( and thus electrically-active polyacetylenes in general ) as " So like and yet so unlike the chalcogenide switches ".

** Significantly, EP0131829 ( a European patent covering much the same material as our patents ) has a US priority date. That is, the initial application was to the US patent office. However, apparently no US patent issued, nor is there a continuation in part or the application withdrawn ( say, to resubmit in another application ). The most reasonable explaination is that the US patent office rejected this patent and the appeals failed.