School of Material Science and Chemical Engineering, Hubei University of Technology, Wuhan 430068, P. R. China.
Soft Matter. 2017 Feb 7;13(5):911-920. doi: 10.1039/c6sm02567f. Epub 2017 Jan 12.
Toughness and self-healing properties are desirable characteristics in engineered hydrogels used for many practical applications. However, it is still challenging to develop hydrogels exhibiting both of these attractive properties in a single material. In this work, we present the fabrication of fully physically-linked Agar/PAAc-Fe DN gels. These hydrogels exhibited dual physical crosslinking through a hydrogen bonded crosslinked agar network firstly, and a physically linked PAAc-Fe network via Fe coordination interactions secondly. Due to this dual physical crosslinking, the fabricated Agar/PAAc-Fe DN gels exhibited very favorable mechanical properties (tensile strength 320.7 kPa, work of extension 1520.2 kJ m, elongation at break 1130%), fast self-recovery properties in Fe solution (100% recovery within 30 min), in 50 °C conditions (100% recovery within 15 min), and under ambient conditions (100% recovery of the initial properties within 60 min), as well as impressive self-healing properties under ambient conditions. All of the data indicate that both the hydrogen bonds in the first network and the ionic coordination interactions in the second network act as reversible sacrificial bonds to dissipate energy, thus conferring high mechanical and recovery properties to the prepared Agar/PAAc-Fe DN gels.
韧性和自修复特性是用于许多实际应用的工程水凝胶的理想特性。然而，在单一材料中同时开发具有这两种有吸引力特性的水凝胶仍然具有挑战性。在这项工作中，我们展示了完全通过物理交联制备的琼脂/PAAc-Fe DN 凝胶。这些水凝胶首先通过氢键交联的琼脂网络进行双重物理交联，其次通过 Fe 配位相互作用进行物理交联的 PAAc-Fe 网络。由于这种双重物理交联，制备的琼脂/PAAc-Fe DN 凝胶表现出非常优异的机械性能（拉伸强度 320.7 kPa，伸长功 1520.2 kJ m，断裂伸长率 1130%），在 Fe 溶液中具有快速的自恢复性能（在 30 分钟内完全恢复），在 50°C 条件下（在 15 分钟内完全恢复），在环境条件下（在 60 分钟内完全恢复初始性能），以及在环境条件下具有令人印象深刻的自修复性能。所有数据表明，第一个网络中的氢键和第二个网络中的离子配位相互作用都作为可逆牺牲键来耗散能量，从而赋予了制备的琼脂/PAAc-Fe DN 凝胶高机械性能和恢复性能。
