Self-assembly of novel catechol-containing copolymers in a nonpolar solvent

Mussel-inspired catechol-containing polymers have a diverse range of potential applications arising from the intra- and inter-molecular interactions enabled by the catechol (CAT) group (i.e. 1,2-dihydroxybenzene). How such interactions underpin self-assembly of catechol-functionalized polymers in non-polar media is of fundamental interest and also critical to their applications but is poorly understood. Here, we have studied the self-assembled nanostructures of four novel catechol-containing polymers in n-dodecane, a model non-polar solvent, using small-angle neutron scattering (SANS). The polymers represented four different architectures - two diblock and two random copolymers, all consisting of a poly(acrylate) backbone with two side chains (a predominant non-polar ethylhexylacrylate (EHA) moiety and a polar catechol-containing moiety (2, 4, or 6 wt% CAT)) in different connectivity. These were also compared with a control homopolymer containing only EHA sidechains. SANS measurements at polymer concentration of 1 wt% in the temperature range T = 20-70 °C showed that the polymer architecture had a significant impact on the morphology of the self-assembled nano-aggregates. These results represent the first experimental observations of self-assembly behaviour of catechol-containing polymers in a non-polar solvent.