Precision, Tunable Deuterated Polyethylene via Polyhomologation

Abstract

The ability to introduce isotopic labeling in a controlled fashion into polymers has long been an area of keen interest, as it allows for analysis by methods such as small-angle neutron scattering. In this work, polyhomologation (also known as “C1 polymerization”) of a deuterated ylide was performed, yielding linear polyethylene of high deuterium content. Copolymerization with the protonated analog allowed for the preparation of statistical copolymers, in which linear polyethylene with a uniform and tunable amount of deuterium is obtained. The amount of deuterium present, as well as its uniform distribution, is supported by vibrational spectroscopy, size-exclusion chromatography with infrared detection, and 2H nuclear magnetic resonance spectroscopy. This technique was extended to prepare a precision triblock copolymer in which the chain-ends are selectively deuterated. All polymers reported are of narrow dispersity, and will find use in myriad measurements sensitive to deuterium labeling, most notably sm...