Tunable Supramolecular Hexagonal Columnar Structures of Hydrogen-Bonded Copolymers Containing Two Different Sized Dendritic Side Chains

Polymer structures with tunable symmetry and sizes are desired for applications such as lithography, filtration membranes, and separation. Here we report the self-assembled supramolecular hexagonal columnar (Φ_H) structures with tunable lattice size varying from 5 to 7 nm by constructing hydrogen-bonded copolymers bearing poly­(4-vinylpyridine) (P4VP) and two dendritic molecular additives, 1-[4′-(3″,4″,5″-tridecyloxybenzoyloxy)­phenyleneoxycarbonyl]-3-[(4″-hydroxyphenyl)­oxycarbonyl]­benzene (12CBP) and 4-hydroxyphenyl (3,4,5-tridecyloxy)­benzoate (12CTB). Despite the distinct molecular size difference between 12CBP and 12CTB, the resulting ternary supramolecular copolymers, P4VP­(12CBP)_<i>x</i>(12CTB)_<i>y</i>, possess a homogeneous Φ_H phase at <i>x</i> ≥ 0.1 and <i>y</i> ≥ 0.2. Each column is constructed with P4VP as the backbone tethered with mixed side chains. The column diameter is between the size of the corresponding P4VP­(12CBP)_{<i>x</i>+<i>y</i>} and P4VP­(12CTB)_{<i>x</i>+<i>y</i>} and could be easily tuned by varying <i>x</i> and <i>y</i>. The enhancement of Φ_H in supramolecular copolymers is attributed to the entropy effect of the mixed side chain and enthalpy effect from hydrogen bonding interaction of the P4VP backbone and two molecules (12CBP and 12CTB).