International audiencePolyurethanes (PUs) constitute a popular class of plastic materials with a wide range of applications in construction, coatings, and the automotive industry. PUs are usually synthesized by step-growth polymerization and, therefore, exhibit non-uniform molecular structures. Here, we show that uniform PUs can be prepared by a facile chemoselective multistep-growth approach. This strategy permits precise control of the chain lengths of the PUs formed and their primary structure, thus making the preparation of coded monomer sequences possible. Furthermore, it was found that these polymers are remarkably easy to analyze by tandem mass spectrometry sequencing. Thus, these precision polymers can potentially be used as molecular barcodes in various applications. As a proof of concept, their use as anti-counterfeiting tags for identification of materials is reported here

High-capacity digital poly(phosphodiester)s were synthesized by stepwise automated phosphoramidite chemistry. Coding libraries containing either 4 or 8 phosphoramidite monomers of different mass were used to encode the polymers, thus enabling storage densities of 2 or 3 bits/monomer, respectively. In addition, a monomer containing a cleavable alkoxyamine and nucleotide mass tags enabling fragment identification were included in the chains to allow their decryption by electrospray pseudo-MS 3 sequencing. As a proof of concept, black and white images with sizes ranging from 80 to 144 pixels were encoded in single polymer chains and decoded by mass spectrometry. Six different polymers were prepared in this work; three with the 4-monomers alphabet and three with the 8-monomers alphabet. In all cases, uniform macromolecules were obtained and deciphered. Yet, the bulkiest monomers of the 8-symbols alphabet required optimized protocols for uniform polymer synthesis. A macromolecular storage capacity of 144 bits per chain was obtained in this work, which is the highest capacity ever attained for a synthetic informational polymer.