Wallace Carothers

On the last day of February 1935, in a DuPont laboratory in Wilmington, Delaware, a chemist named Gerard Berchet combined hexamethylenediamine with adipic acid and pulled from the flask a polyamide the world would come to know as nylon. Two days earlier, on February 26, a Scottish engineer named Robert Watson-Watt had quietly demonstrated that radio waves could detect an aircraft. This was the birth of radar. In one extraordinary week, the twentieth century acquired both its electronic eyes and its synthetic thread. Elsewhere that year, Americans were buying a brand-new board game called Monopoly and Congress was inventing Social Security. The modern world was assembling itself, piece by piece, and the man who had directed that Wilmington experiment was Wallace Hume Carothers.

An Iowa Boy with a Theoretical Mind

Carothers was born in Burlington, Iowa, in 1896, and his talent announced itself early and loudly. He collected degrees the way other people collect stamps: a bachelor’s from tiny Tarkio College, then a master’s at Illinois under Carl Marvel, then a doctorate in 1924 under the legendary Roger Adams. By 1926 he was teaching organic chemistry at Harvard. That is, by any reasonable measure, the summit of an academic career trajectory, which makes what happened next all the more interesting.

In 1928, DuPont came calling with a radical idea: a corporate laboratory devoted to fundamental research: science for understanding’s sake, with no product deadline in sight. Carothers said no at first (he doubted himself far more than his employers did), but the executive Hamilton Bradshaw persuaded him, and on February 6, 1928, the 31-year-old took charge of organic chemistry at the DuPont Experimental Station. His colleagues nicknamed the pristine new laboratory “Purity Hall.”

Purity Hall Pays Off

Carothers arrived with an agenda that sounded almost quaint: prove, by careful synthesis, that Staudinger’s controversial macromolecules were real. If molecules truly could be giant chains, then a chemist should be able to build one deliberately, link by link, using nothing but well-understood reactions. It was molecular bricklaying against a backdrop of theoretical chaos, and it worked beyond anyone’s dreams.

In April 1930 (the same spring astronomers were celebrating the discovery of Pluto) Purity Hall struck twice. First, Arnold Collins, working under Carothers’ direction, isolated chloroprene and produced the first commercially successful synthetic rubber, later named neoprene. Then Julian Hill, reaching into a flask of experimental polyester, discovered that the cooled filaments could be cold-drawn: stretched into silky threads several times their length, the molecules aligning like combed hair. This was a discovery reportedly celebrated by seeing how far down the corridor a filament could be stretched. Using their “molecular still” to coax condensation reactions ever further, the group pushed polyesters to molecular weights around 12,000, numbers that made colloid-theory diehards distinctly uncomfortable.

The polyesters melted too low for practical fibers, so Carothers turned from esters to amides, and in February 1935 the group’s methodical search delivered polyamide 6,6, a fiber with the strength and sheen of silk and the soul of coal tar, water, and air. Along the way Carothers gave polymer science one of its foundational pieces of theory: the Carothers equation, relating a step-growth polymer’s chain length to the extent of reaction. The equation is the mathematical reason patience (and obsessive stoichiometry) is a polymer chemist’s cardinal virtue.

The Weight of a Brilliant Mind

The spring of 1936 looked golden from the outside. On February 21 he married Helen Sweetman, a DuPont colleague; on April 30 he became the first industrial organic chemist ever elected to the National Academy of Sciences. But Carothers had struggled with severe depression for much of his adult life, and fame provided no protection. He spoke of himself with punishing modesty, confessing to a friend that he felt he was “accepting incalculable benefits” while failing to give even a trivial return. The death of his beloved sister Isobel in January 1937 deepened a darkness that his doctors already considered grave.

On April 29, 1937 (two days past his forty-first birthday) Wallace Carothers took his own life in a Philadelphia hotel room. The disease that took him was as real as any studied in a laboratory, and it took him at the height of his powers. Seven months later, on November 27, his daughter Jane was born.

The Triumph He Never Saw

Sixteen months after his death, on October 27, 1938, DuPont announced nylon to the public at the site of the coming New York World’s Fair. When the first 4,000 pairs of nylon stockings went on sale in Wilmington in October 1939, they vanished in three hours. On “Nylon Day” in May 1940, stockings reached the whole nation; 64 million pairs sold in the first year. Then came war, parachutes, and the rest of the story, told on this Atlas’s nylon page.

Carothers left behind roughly nine years of industrial research. Out of them came the first synthetic rubber, the first fully synthetic fiber, the experimental proof of macromolecular theory, and the theoretical framework of step-growth polymerization. Nearly a century later, polymer chemists still work inside the walls he built, and his equation still tells them exactly how far their reactions have to go.