Analysis of monodisperse, sequence-defined, and POSS-functionalized polyester copolymers by MALDI tandem mass spectrometry.

Monodisperse, sequence-defined polymers can be potentially used for digital data storage. This study reports the sequence analysis and differentiation of monodisperse polyester copolymers carrying side chains functionalized in a specific order by polyhedral oligomeric silsesquioxane (POSS) nanoparticles. Steglich esterification and succinic anhydride ring-opening chemistries were utilized iteratively to synthesize the intended sequences, which were characterized by matrix-assisted laser desorption ionization tandem mass spectrometry (MALDI-MS2 ). Isomeric oligomers were readily distinguished based on their different fragmentation patterns. The sequences embedded in the oligomers were decrypted by their specific backbone dissociation pathways. The robustness of using MALDI-MS2 as a sequencing method for monodisperse synthetic macromolecules was assessed and validated by the characterization of longer oligomers.