Nucleobase self-assembly in supramolecular adhesives

Novel acrylic monomers functionalized with nucleobase-containing units (adenine and thymine) were prepared upon aza-Michael addition and successfully copolymerized with n-butyl acrylate. At a content of 7 mol %, adenine-containing units self-assembled into needle-like microstructures within amorphous polymer matrices as shown with atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), and wide-angle X-ray diffraction (WAXD); thymine-containing units did not aggregate into distinct morphologies even to 30 mol %. Upon blending, thymine- and adenine-containing statistical copolymers associated into a thermodynamically stable complex, which was physically cross-linked through adenine-thymine base pairing. The molar fractions of the nucleobase monomer, nucleobase stacking interactions, and complementary hydrogen bonding principally influenced self-assembly. Additionally, the nucleobase-functionalized polyacrylates exhibited tunable adhesive and cohesive strength.