Strategy for Enhancing Ultrahigh-Molecular-Weight Block Copolymer Chain Mobility to Access Large Period Sizes (>100 nm)

• Published in: Langmuir Vol. 36; no. 46; pp. 13872 - 13880
• Main Authors: Cummins, Cian, Alvarez-Fernandez, Alberto, Bentaleb, Ahmed, Hadziioannou, Georges, Ponsinet, Virginie, Fleury, Guillaume
• Format: Journal Article
• Language: English
• Published: American Chemical Society 24-11-2020
• Subjects: Chemical Sciences; Polymers; surface chemistry; optical nanoresonators; metasurfaces; Block copolymers; large period patterning
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.0c02261

Assembling ultrahigh-molecular-weight (UHMW) block copolymers (BCPs) in rapid time scales is perceived as a grand challenge in polymer science due to slow kinetics. Through surface engineering and identifying a nonvolatile solvent (propylene glycol methyl ether acetate, PGMEA), we showcase the impressive ability of a series of lamellar poly­(styrene)-block-poly­(2-vinylpyridine) (PS-b-P2VP) BCPs to self-assemble directly after spin-coating. In particular, we show the formation of large-period (≈111 nm) lamellar structures from a neat UHMW PS-b-P2VP BCP. The significant influence of solvent–polymer solubility parameters are explored to enhance the polymer chain mobility. After optimization using solvent vapor annealing, increased feature order of ultralarge-period PS-b-P2VP BCP patterns in 1 h is achieved. Isolated metallic and dielectric features are also demonstrated to exemplify the promise that large BCP periods offer for functional applications. The methods described in this article center on industry-compatible patterning schemes, solvents, and deposition techniques. Thus, our straightforward UHMW BCP strategy potentially paves a viable and practical path forward for large-scale integration in various sectors, e.g., photonic band gaps, polarizers, and membranes that demand ultralarge period sizes.