Wang Runda, Lei Yiteng, Zhu Tao, Fan Rong, Jiang Zhongying, Sheng Jie
Key Laboratory of Micro-nano Electric Sensing Technology and Bionic Devices, Department of Network Security and Information Technology, Yili Normal University, Yining 835000, P. R. China.
Department of Electronics and Engineering, Yili Normal University, Yining 835000, P. R. China.
ACS Omega. 2023 Sep 20;8(39):35619-35627. doi: 10.1021/acsomega.3c01813. eCollection 2023 Oct 3.
Synthetic hydrogels struggle to match the high strength, toughness, and recoverability of biological tissues under periodic mechanical loading. Although the hydrophobic polymer chain of polystyrene (PS) may initially collapse into a nanosphere upon contact with water, it has the ability to be elongated when it is subjected to an external force. To address this challenge, we employ the reversible addition-fragmentation chain transfer (RAFT) method to design a carboxyl-substituted polystyrene (CPS) which can form a covalently cross-linked network with four-armed amino-terminated polyethylene glycol (4-armed-PEG-NH), and a ductile polyacrylamide network is introduced in order to prepare a double-network (DN) hydrogel. Our results demonstrate that the DN hydrogel exhibits exceptional mechanical properties (0.62 kJ m fracture energy, 2510.89 kJ m toughness, 0.43 MPa strength, and 820% elongation) when a sufficient external force is applied to fracture it. Moreover, when the DN hydrogel is subjected to a 200% strain, it displays superior recoverability (94.5%). This holds a significant potential in enhancing the mechanical performance of synthetic hydrogels and can have wide-ranging applications in fields such as tissue engineering for hydrophobic polymers.
在周期性机械负载下，合成水凝胶难以达到生物组织的高强度、韧性和可恢复性。尽管聚苯乙烯（PS）的疏水聚合物链在与水接触时最初可能会塌缩成纳米球，但在受到外力作用时它有被拉长的能力。为应对这一挑战，我们采用可逆加成-断裂链转移（RAFT）方法设计一种羧基取代的聚苯乙烯（CPS），它能与四臂氨基封端的聚乙二醇（4-臂-PEG-NH）形成共价交联网络，并引入韧性聚丙烯酰胺网络以制备双网络（DN）水凝胶。我们的结果表明，当施加足够的外力使其断裂时，DN水凝胶表现出优异的力学性能（断裂能为0.62 kJ m，韧性为2510.89 kJ m，强度为0.43 MPa，伸长率为820%）。此外，当DN水凝胶受到200%的应变时，它表现出卓越的可恢复性（94.5%）。这在增强合成水凝胶的力学性能方面具有巨大潜力，并且在诸如疏水聚合物的组织工程等领域可能有广泛应用。
