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 (fP_S) was investigated via small-angle X-ray scattering and transmission electron microscopy. With increasing fP_S 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 fP_S = 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.

This work was supported by the National Creative Research Initiative Program supported by the National Research Foundation of KOREA(2013R1A3A2042196).