In an exciting development in materials science, a team of researchers from ETH Zurich has developed an exciting method known as Elastic Microphase Separation (EMPS) to create intricate and versatile structures in materials. This new technique, distinct from traditional methods, could revolutionize various applications across various fields, from engineering to biotechnology.
The paper, published in Nature, details not only the technical aspects of EMPS but also its potential to inspire innovative applications, such as replicating the complex structures found in bird feathers.
The researchers were inspired by the feathers of the North American song bird. Image Credit: PETER LAKOMY/Shutterstock.com
At the heart of this discovery is the concept of balancing molecular-scale forces against large-scale elasticity to achieve a unique thermodynamic length scale. This method is notably characterized by its continuous phase transition, which is reversible and free from hysteresis - a significant departure from traditional models. The practical aspect of EMPS is its simple triggering mechanism: supersaturating an elastomeric matrix with a liquid. This results in uniform materials characterized by a microstructure whose scale can be precisely tuned via the stiffness of the matrix.
One of the remarkable features of this technique is its ability to replicate structures akin to bird feathers. By finely controlling the phase separation process and the resulting microstructure, researchers have been able to mimic the intricate design of feather barbs and barbules. This biomimicry not only highlights the precision of EMPS but also opens avenues for creating materials with specific, nature-inspired properties.
Versatility and Application
The versatility of EMPS is further underscored through the fabrication of materials that boast superior mechanical properties, controlled anisotropy, and microstructural gradients. The methodology detailed in the study includes a process where the oil-rich microphase is gradually transported out of the network and the subsequent stabilization through polymerization of methacrylate-functionalized HFBMA post-phase separation.
This procedure culminates in a material that remains stable and retains its structure for at least 12 months.
In terms of mechanical properties, the EMPS process, followed by polymerization, significantly enhances the toughness and Young’s modulus of elastomers. This results in a composite elastomer that exhibits not only heightened stiffness but also an impressive ability to withstand substantial strains.
The implications of such enhanced mechanical performance are vast, ranging from improved wearables to advanced engineering materials.
Implications for Soft Matter and Materials Science
This novel approach to fabricating bicontinuous materials challenges traditional models of phase separation, suggesting that continuous, hysteresis-free transitions are accessible beyond near-critical points. EMPS necessitates a new theoretical framework, one that incorporates the interplay of mechanics and thermodynamics in a way not previously considered. The implications for soft matter and materials science are profound, as it potentially sheds light on emerging questions in fields as diverse as biology and mechanical engineering.
Future Prospects
Looking ahead, the potential applications of EMPS are vast and varied. The research suggests the possibility of reducing the microstructural length scale to produce materials with structural colors akin to those found in nature. There is also the prospect of optimizing the toughness of elastomers for applications in wearable technology. Additionally, the selective removal of one phase could lead to materials with novel filtration, energy storage, and catalytic properties, hinting at a future where EMPS plays a central role in the development of advanced functional materials.
Source
Fernández-Rico, C., Schreiber, S., Oudich, H. et al. Elastic microphase separation produces robust bicontinuous materials. Nat. Mater. (2023). https://doi.org/10.1038/s41563-023-01703-0