Graduate School of Life Science, Hokkaido University, Sapporo, 001-0021, Japan.
Faculty of Advanced Life Science, Hokkaido University, Sapporo, 001-0021, Japan and Global Station for Soft Matter, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, 001-0021, Japan.
J Mater Chem B. 2019 Sep 11;7(35):5296-5305. doi: 10.1039/c9tb01376h.
Polyelectrolyte complexation between oppositely charged polyelectrolytes forms coacervates in dilute solutions and thin films in concentrated solutions. It is difficult to obtain macroscopically uniform bulk polyelectrolyte complex (PEC) materials, since the two polymers form insoluble complexes quickly at the contact interface during mixing, resulting in heterogeneous aggregates. Here, we succeeded in preparing bulk PEC materials based on desalting-induced polyelectrolyte complexation via viscoelastic phase separation. With a high ionic strength aqueous medium, a homogeneous and concentrated solution containing oppositely charged polyelectrolytes is prepared. Desalting of the counter-ions and co-ions of the solution through semi-permeable membranes induces viscoelastic phase separation of the solution to form a physical hydrogel with open pore structure. Regulating the charge ratio of the two oppositely charged polymers results in significant changes in the porous morphology and mechanical properties. The charge-balanced PEC hydrogels show unique properties including high toughness and self-recovery due to the reversible ionic associations. The porous yet tough properties of bulk PEC hydrogels makes them potential candidates for applications such as cell scaffolds.
带相反电荷的聚电解质之间的聚电解质络合在稀溶液中形成凝聚体，在浓溶液中形成薄膜。由于两种聚合物在混合过程中在接触界面处迅速形成不溶性复合物，导致异质聚集，因此很难获得宏观均匀的大块聚电解质复合物（PEC）材料。在这里，我们通过粘弹相分离成功地制备了基于脱盐诱导聚电解质络合的大块 PEC 材料。在高离子强度的水介质中，制备了含有带相反电荷的聚电解质的均匀且浓缩的溶液。通过半透膜对溶液中的抗衡离子和共离子进行脱盐，诱导溶液发生粘弹相分离，形成具有开放孔结构的物理水凝胶。调节两种带相反电荷的聚合物的电荷比会导致多孔形态和力学性能的显著变化。由于可逆的离子缔合，电荷平衡的 PEC 水凝胶表现出独特的性能，包括高韧性和自恢复性。大块 PEC 水凝胶的多孔且坚韧的特性使它们成为细胞支架等应用的潜在候选材料。
