Fang Zhang, Changyuan Song, Xiangwei Zhu, Jiang Gong and Qiang Zhao*
Tardigrades inspired polyelectrolyte complexation and functional materials
Cryptobiosis and the modulated macromolecular assembly at dynamic water ~ ice interfaces are crucial to Tardigrades’ survival in extremely low temperature. This inspires the shape memory assembly of oppositely charged polyelectrolytes at dynamic phase changes spanning water freezing temperatures, in stark contrast to conventional polymer self-assembly that mainly occur in solution. A weak polyanion and a polycation was mixed in dimethyl sulphoxide and sprayed into liquid nitrogen. Frozen microparticles were transferred to ethanol-ammonia solution, whereby polyelectrolyte complexation was simultaneously coupled to the particle thawing to retain particle shapes. It represents a versatile method to process insoluble polyelectrolyte complexes (PECs), as further demonstrated by the preparation of PEC microcapsules, porous monoliths and hybrid membranes. This work established a paradigm shift of macromolecular assembly from solution to freeze-thaw dynamic interfaces, opening doors to progressive polyelectrolyte complexation for energy and enviromental implications as exemplified here by solar thermal desalination membranes.