Design and Morphological Investigation of High-chi Catechol-Containing Styrenic Block Copolymers

We report the synthesis of multifunctional block copolymers (BCPs) showing a high Flory-Huggins interaction parameter (chi), which enable sub-10 nm line-space structures for a low degree of polymerization (N). The high chi BCPs are based on a poly(3,4-dihydroxystyrene)-block-poly(4-trimethylsilylstyrene) (PDHS-b-PTMSS) architecture. The controlled synthesis of the PDHS-b-PTMSS precursors was performed using user-friendly sequential nitroxide mediated polymerization (NMP) of poly(3,4-diacetoxystyrene) and block-poly(4-trimethylsilylstyrene) (PDAS-b-PTMSS). Thereafter, acid-catalyzed deprotection of the acetoxy moieties produced a library of PDHS-b-PTMSS BCPs with molecular weights ranging from 2.1 to 44.5 kg/mol. Bulk lamellar and cylindrical structures with periodicities as small as 8 nm were revealed by small-angle X-ray scattering. Moreover, PDHS-b-PTMSS thin films were assembled using solvent vapor annealing to define 10 nm line-space patterns in favorable conditions, i.e., at 20 degrees C for 20 min. In summary, our work brings further knowledge to the BCP toolbox for next-generation nanomanufacturing needs.