State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, PR China.
ACS Appl Mater Interfaces. 2018 Jan 24;10(3):2897-2906. doi: 10.1021/acsami.7b14588. Epub 2018 Jan 9.
The fabrication of shape-memory polymers or films that can simultaneously heal the mechanical damage and the fatigued shape-memory function remains challenging. In this study, mechanically robust healable shape-memory polymeric films that can heal the mechanical damage and the fatigued shape-memory function in the presence of water are fabricated by layer-by-layer assembly of branched poly(ethylenimine) (bPEI)-graphene oxide (GO) complexes with poly(acrylic acid) (PAA), followed by the release of the (PAA/bPEI-GO)*n films from the underlying substrates. The free-standing (PAA/bPEI-GO)*35 films made of bPEI-GO complexes with a mass ratio of 0.02 between GO nanosheets and bPEI are mechanically robust with a Young's modulus of 19.8 ± 2.1 GPa and a hardness of 0.92 ± 0.15 GPa and exhibit excellent humidity-induced healing and shape-memory functions. Benefiting from the highly efficient healing function, the (PAA/bPEI-GO)*35 films can heal cuts penetrating thorough the entire film and achieve an ∼100% shape-recovery ratio for a long-term shape-memory application. Meanwhile, the shape-memory function of the mechanically damaged (PAA/bPEI-GO)*35 films can be finely restored after being healed in water. The shape-memory functions of the (PAA/bPEI-GO)*35 films and their healing capacity originate from the reversibility of electrostatic and hydrogen-bonding interactions induced by water between PAA and bPEI-GO complexes.
制备同时具有机械损伤自修复和疲劳形状记忆功能的形状记忆聚合物或薄膜仍然具有挑战性。在这项研究中，通过层层组装支化聚乙烯亚胺(bPEI)-氧化石墨烯(GO)复合物与聚丙烯酸(PAA)，制备了具有机械强度的可修复形状记忆聚合物薄膜，在水的存在下可以修复机械损伤和疲劳形状记忆功能，然后将(PAA/bPEI-GO)*n 薄膜从基底上释放。由 bPEI-GO 复合物组成的自由支撑的(PAA/bPEI-GO)*35 薄膜，其中 GO 纳米片和 bPEI 的质量比为 0.02，具有 19.8±2.1 GPa 的杨氏模量和 0.92±0.15 GPa 的硬度，表现出优异的湿度诱导自修复和形状记忆功能。得益于高效的自修复功能，(PAA/bPEI-GO)*35 薄膜可以修复贯穿整个薄膜的切口，并实现长期形状记忆应用的约 100%形状恢复率。同时，机械损伤的(PAA/bPEI-GO)*35 薄膜在水中修复后，其形状记忆功能可以得到很好的恢复。(PAA/bPEI-GO)*35 薄膜的形状记忆功能及其修复能力源于 PAA 和 bPEI-GO 复合物之间的水诱导静电和氢键相互作用的可逆性。
