Synthesis of supramolecular precision polymers: Crystallization under conformational constraints

Article abstract of DOI:10.1002/pola.28759

Placing artificial folding elements into precision polymers is an important strategy to systematically study structure formation in self-assembly, particularly in the semicrystalline state. To this purpose, a series of precision polymers bearing either a N-protected or N-unprotected diaminopyridine (DAP) unit after every 16th, 18th, and 20th carbon as well as a urea unit after every 20th carbon along a polyethylene-like polymer were synthesized via acyclic diene metathesis polymerization and subsequent hydrogenation. The polymers thus contain either H-bonds (urea/DAP), π–π-elements (DAP), or no H-bonds (respective N?protected urea/DAP-units) in their main chain, able to consequently study the crystallization behavior under influence of such supramolecular moieties. Therefore, the thermal properties and crystallization behavior were analyzed via differential scanning calorimetry (DSC) as well as wide angle X-ray diffraction. The obtained crystalline polymer is influenced by the different supramolecular interactions existing between adjacent polymer chains and the varying defect size exerted by the incorporated functional groups.