Phase behavior of poly(9-(4-vinylbenzyl)adenine)-block-polystyrene copolymers

In this study, we successfully synthesized adenine-containing block copolymers, poly(9-(4-vinylbenzyl)adenine)-block-polystyrene (PVBA-b-PS), using reversible addition-fragmentation chain transfer (RAFT) polymerization and characterized them by size exclusion chromatography, and nuclear magnetic resonance spectroscopy.
The phase behavior of PVBA-b-PS with various volume fractions of PS block (f_PS) was investigated via small-angle X-ray scattering and transmission electron microscopy. With increasing f_PS from 0.1 to 0.8, body-centered-cubic spheres of PS, hexagonally packed (HEX) cylinders of PS, lamellae, and HEX cylinders of PVBA were observed. Interestingly, PVBA-b-PS with f_PS = 0.75 showed asymmetric lamellar microdomains.
We also prepared thin film of PVBA-b-PS on a substrate as a template for spatial arrangement of gold nanoparticles (AuNPs). When the surface of AuNPs was modified with thymine-containing polymer chains, AuNPs were selectively sequestered into PVBA microdomains through the complementary hydrogen bonding between thymine and adenine units.