Open AccessStabilizing a Double Gyroid Network Phase with 2 nm Feature Size by Blending of Lamellar and Cylindrical Forming Block Oligomers
Author(s) -
Zhengyuan Shen,
Kui Luo,
So Jung Park,
Daoyuan Li,
Mahesh Mahanthappa,
Frank S. Bates,
Kevin D. Dorfman,
Timothy P. Lodge,
J. Ilja Siepmann
Publication year - 2022
Publication title -
jacs au
Language(s) - English
Resource type - Journals
ISSN - 2691-3704
DOI - 10.1021/jacsau.2c00101
Subject(s) - gyroid , lamellar structure , materials science , amphiphile , phase (matter) , lamellar phase , copolymer , molecular dynamics , polymer , block (permutation group theory) , chemical physics , chemical engineering , crystallography , polymer chemistry , composite material , chemistry , computational chemistry , organic chemistry , geometry , mathematics , engineering
Molecular dynamics simulations are used to study binary blends of an AB-type diblock and an AB 2 -type miktoarm triblock amphiphiles (also known as high-χ block oligomers) consisting of sugar-based (A) and hydrocarbon (B) blocks. In their pure form, the AB diblock and AB 2 triblock amphiphiles self-assemble into ordered lamellar (LAM) and cylindrical (CYL) structures, respectively. At intermediate compositions, however, the AB 2 -rich blend (0.2 ≤ x AB ≤ 0.4) forms a double gyroid (DG) network, whereas perforated lamellae (PL) are observed in the AB-rich blend (0.5 ≤ x AB ≤ 0.8). All of the ordered mesophases present domain pitches under 3 nm, with 1 nm feature sizes for the polar domains. Structural analyses reveal that the nonuniform interfacial curvatures of DG and PL structures are supported by local composition variations of the LAM- and CYL-forming amphiphiles. Self-consistent mean field theory calculations for blends of related AB and AB 2 block polymers also show the DG network at intermediate compositions, when A is the minority block, but PL is not stable. This work provides molecular-level insights into how blending of shape-filling molecular architectures enables network phase formation with extremely small feature sizes over a wide composition range.