The design of complex fluids and soft matter structures is a present challenge in supramolecular and polymer chemistry as well as in nano-science and touches the question of the development of biological relevant structures from aqueous fluids. Bicontinuous networks are widely found at different length scales and provide promising applications in photonics and electronics, metamaterials, supercapacitors, catalysts, templates and membranes for separation and filtration, etc. The understanding of the transition between double diamond (DD) and double gyroid (DG) networks is still unclear and the search for new intermediate structures represents a current research topic in the abovementioned areas of science. Here, we report a novel phase sequence from DD to DG cubic phases via two non-cubic intermediate phases, an orthorhombic Fmmm phase and a hexagonal P63/m phase in specifically designed bolapolyphiles. There is a step-by-step transition of junctions during the gyroid-diamond transition: from the tetrahedral junctions with CN = 4 in the DD phase via distorted tetrahedral junctions in Fmmm and distorted trigonal junctions in P63/m to regular trigonal junctions with CN = 3 in the DG phase. The phase transition process not only satisfies the desire of optimized sphere packing, but also optimizes the local rod and chain packings. The formation of four phases is due to the competition between triply periodic minimal surface and dense packing of junctions. This work contributes to the understanding of the fundamental principles underlying the development of structural complexity in fluids, being a prerequisite for the emergence of life from aqueous systems and leading to new soft-matter nano-structures for numerous potential applications.
These results were published on Journal of the American Chemical Society entitled Network Phases with Multiple-Junction Geometries at the Gyroid−Diamond Transition. The co-first author of this work are Xiaoqian Cai (Ph.D. candidate at Xi’an Jiaotong University) and Sebastian Hauche (Ph.D. candidate at Martin-Luther University Halle-Wittenberg). The corresponding authors are Prof. Feng Liu (Xi’an Jiaotong University, School of Materials Science and Engineering) and Prof. Carsten Tschierske (Martin-Luther University Halle-Wittenberg, Institute of Chemistry). The research was funded by National Natural Science Foundation of China and the Deutsche Forschungsgemeinschaft.
Link: https://pubs.acs.org/doi/10.1021/jacs.2c10462
