A Tetragonal Phase Self-Organized from Unimolecular Spheres Assembled from a Substituted Poly(2-oxazoline)

作者：Holerca Marian N; Sahoo Dipankar; Peterca Mihai; Partridge Benjamin E; Heiney Paul A; Percec Virgil^*

来源：Macromolecules, 2017, 50(1): 375-385.

DOI：10.1021/acs.macromol.6b02298

Synthesis and living cationic ring-opening polymerization of a 2-oxazoline containing self-assembling minidendrons with hexadecyl groups are reported. Structural analysis using X-ray diffraction, molecular modeling, and reconstructed electron density maps revealed multiple self organized periodic arrays, including columnar hexagonal P6mm, cubic Pm (3) over barn, and tetragonal P4(2)/mnm phases, which have not been observed before in a single homopolymer. The degree of polymerization (DP) of the poly(2-oxazoline) programs the sequence of these periodic arrays. The cubic Pm (3) over barn phase was observed for DP = 5 whereas the tetragonal P4(2)/mnm for 10 <= DP <= 50. For DP >= 75, only a columnar hexagonal P6mm phase was accessible because the polymer chains are too long to form a single supramolecular sphere. This sequence was rationalized by the columnar character of supramolecular spheres to provide the richest diversity of structures assembled from a single polymer and an unprecedented example of a tetragonal phase organized from niacromolecular spheres comprising a single polymer chain.

• 出版日期2017-1-10