Elastic microphase separation produces robust bicontinuous materials

• Published in: Nature materials Vol. 23; no. 1; pp. 124 - 130
• Main Authors: Fernández-Rico, Carla, Schreiber, Sanjay, Oudich, Hamza, Lorenz, Charlotta, Sicher, Alba, Sai, Tianqi, Bauernfeind, Viola, Heyden, Stefanie, Carrara, Pietro, Lorenzis, Laura De, Style, Robert W., Dufresne, Eric R.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 2024; Nature Publishing Group
• Subjects: 639/301/923/1027; 639/301/923/1028; 639/301/923/966; Anisotropy; Biomaterials; Block copolymers; Chemistry and Materials Science; Condensed Matter Physics; Elastomers; Fabrication; Materials Science; Mechanical properties; Microstructure; Nanotechnology; Optical and Electronic Materials; Phase separation; Phase transitions; Robustness; Self-assembly; Stiffness; Thermodynamics
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-023-01703-0

Bicontinuous microstructures are essential to the function of diverse natural and synthetic systems. Their synthesis has been based on two approaches: arrested phase separation or self-assembly of block copolymers. The former is attractive for its chemical simplicity and the latter, for its thermodynamic robustness. Here we introduce elastic microphase separation (EMPS) as an alternative approach to make bicontinuous microstructures. Conceptually, EMPS balances the molecular-scale forces that drive demixing with large-scale elasticity to encode a thermodynamic length scale. This process features a continuous phase transition, reversible without hysteresis. Practically, EMPS is triggered by simply supersaturating an elastomeric matrix with a liquid, resulting in uniform bicontinuous materials with a well-defined microscopic length scale tuned by the matrix stiffness. The versatility of EMPS is further demonstrated by fabricating bicontinuous materials with superior mechanical properties and controlled anisotropy and microstructural gradients. Overall, EMPS presents a robust alternative for the bulk fabrication of homogeneous bicontinuous materials. Production of bulk bicontinuous materials is limited by the ability to make uniform microarchitectures across large volumes. Here elastic microphase separation is used to fabricate bicontinuous materials with a homogeneous microstructure, with feature sizes tuned by the matrix stiffness.