Nature consists of various soft tissues with well-ordered hierarchical anisotropic structures, which play essential roles in biological systems to exhibit particular functions. Mimicking bio-tissues, synthetic hydroge...Nature consists of various soft tissues with well-ordered hierarchical anisotropic structures, which play essential roles in biological systems to exhibit particular functions. Mimicking bio-tissues, synthetic hydrogels with anisotropic structures have received considerable attention in recent years. However, existing approaches to fabricate anisotropic hydrogels often require complicated procedures, which are timeconsuming and labor-demanding. Inspired by the dry-induced crystallization phenomenon, we report a simple yet effective prestretching-drying-swelling method to afford anisotropic crystalline polyvinyl alcohol hydrogels. Owing to the distinct anisotropic microstructure, the hydrogels demonstrate excellent mechanical properties with noticeable directional distinction. It is revealed that both the enhancing of pre-orientation strain and the extending of heating time make the hydrogels with better mechanical properties and more remarkable anisotropicity. Owing to the anisotropically aligned structure, the hydrogels exhibit remarkably differential ionic conductivity: the difference between the parallel and vertical conductivity of the same sample can reach as high as 6.6 times, making the materials possible candidates as nano-conductive materials. We anticipate that this simple yet effective approach may become highly useful for fabricating oriented hydrogels and endow the materials with more promising application prospects in the future.展开更多
基金financial support from the National Key Research and Development Program of China (No.2019YFE0111000)the National Natural Science Foundation of China (NSFC,Nos.51903253,51903257)+2 种基金Natural Science Foundation of Guangdong Province of China (Nos.2019A1515011150,2019A1515011258)Macao University of Science and Technology Foundation (No.FRG-19-003-SP)the Science and Technology Development Fund of Macao (Nos.FDCT 0009/2019/A,0083/2019/A2,0007/2019/AKP)。
文摘Nature consists of various soft tissues with well-ordered hierarchical anisotropic structures, which play essential roles in biological systems to exhibit particular functions. Mimicking bio-tissues, synthetic hydrogels with anisotropic structures have received considerable attention in recent years. However, existing approaches to fabricate anisotropic hydrogels often require complicated procedures, which are timeconsuming and labor-demanding. Inspired by the dry-induced crystallization phenomenon, we report a simple yet effective prestretching-drying-swelling method to afford anisotropic crystalline polyvinyl alcohol hydrogels. Owing to the distinct anisotropic microstructure, the hydrogels demonstrate excellent mechanical properties with noticeable directional distinction. It is revealed that both the enhancing of pre-orientation strain and the extending of heating time make the hydrogels with better mechanical properties and more remarkable anisotropicity. Owing to the anisotropically aligned structure, the hydrogels exhibit remarkably differential ionic conductivity: the difference between the parallel and vertical conductivity of the same sample can reach as high as 6.6 times, making the materials possible candidates as nano-conductive materials. We anticipate that this simple yet effective approach may become highly useful for fabricating oriented hydrogels and endow the materials with more promising application prospects in the future.
