Light-Responsive Self-Assembled Materials by Supramolecular Post-Functionalization via Hydrogen Bonding of Amphiphilic Block Copolymers

A new class of light-responsive supramolecular amphiphilic block copolymers (BCs) based on the association through multiple H-bonding between 4-isobutyloxyazobenzene motifs and 2,6-diacylaminepyridine units is reported. Block copolymers containing 2,6-diacylaminopyridine side units, as hydrophobic block, and poly­(ethylene glycol), as a hydrophilic segment, were functionalized with either a carboxylic acid azodendron, via double H-bonding, or a thymine azobenzene, via triple H-bonding. The structural and thermal characterization of these supramolecular azo-copolymers in bulk and solution is presented. The work emphasizes the self-assembly of these supramolecular polymers in water and the study of their UV-light responsive properties by UV–vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and synchrotron small-angle X-ray (SAXS). The present noncovalent postpolymerization functionalization strategy has provided stable self-assemblies in water with light responsive properties that can be used to load and trigger the delivery of small fluorescent molecules.