Molecular Architecture Directs Linear–Bottlebrush–Linear Triblock Copolymers to Self-Assemble to Soft Reprocessable Elastomers

Journal Article · 01 November 2019 · ACS Macro Letters

DOI: https://doi.org/10.1021/acsmacrolett.9b00721 · OSTI ID:1580235

Nian, Shifeng ^[1]; Lian, Huada ^[2]; Gong, Zihao ^[1]; Zhernenkov, Mikhail  ^[3]; Qin, Jian  ^[2]; Cai, Li -Heng  ^[1]

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1. Univ. of Virginia, Charlottesville, VA (United States)
2. Stanford Univ., Stanford, CA (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States)

Linear–bottlebrush–linear (LBBL) triblock copolymers represent an emerging system for creating multifunctional nanostructures. Their self-assembly depends on molecular architecture but remains poorly explored. We synthesize polystyrene-block-bottlebrush polydimethylsiloxane-block-polystyrene triblock copolymers with controlled molecular architecture and use them as a model system to study the self-assembly of LBBL polymers. Unlike classical stiff rod-flexible linear block copolymers that are prone to form highly ordered nanostructures such as lamellae, at small weight fractions of the linear blocks, LBBL polymers self-assemble to a disordered sphere phase, regardless of the bottlebrush stiffness. Microscopically, characteristic lengths increase with the bottlebrush stiffness by a power of 2/3, which is captured by a scaling analysis. Macroscopically, the formed nanostructures are ultrasoft, reprocessable elastomers with shear moduli of about 1 kPa, two orders of magnitude lower than that of conventional polydimethylsiloxane elastomers. Our results provide insights on exploiting the self-assembly of LBBL polymers to create soft functional nanostructures.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
• Grant/Contract Number: SC0012704
• OSTI ID: 1580235
• Report Number(s): BNL-212460-2019-JAAM
• Journal Information: ACS Macro Letters, Vol. 8, Issue 11; ISSN 2161-1653
• Publisher: American Chemical Society (ACS)Copyright Statement
• Country of Publication: United States
• Language: English