金属有机框架(MOF)在开发用于柔性换能器的可拉伸和可磨损的导电水凝胶方面引起了极大的关注。然而,在水凝胶网络中使用的MOFs受到低机械性能和在水溶液中分散性差的阻碍。影响水凝胶的性能,包括低韧性,自我恢复有限,工作范围短,低电导率,和延长的响应-恢复时间。为了解决这些缺点,采用了一种新颖的方法,其中胶束共聚用于非原位合成Zn-MOF基水凝胶,具有出色的拉伸性,坚固的韧性,抗疲劳性能,良好的导电性。这一突破涉及Zn-MOF非原位整合到疏水交联的聚合物链中。这里EHDDAB的胶束有两个功能,首先它们均匀分散Zn-MOFs,其次它们动态交联聚合物链,深刻影响水凝胶的力学特性。Zn-MOFs引入的非共价协同相互作用使水凝胶具有高拉伸性,高应力,快速自我恢复,抗疲劳性能,和导电性,所有这些都是在没有外部刺激的情况下实现的。此外,基于Zn-MOFs的水凝胶可以作为耐用和高度敏感的柔性传感器,擅长检测不同的机械变形,具有快速的响应恢复时间和高的仪表系数值。因此,这些水凝胶可以被定制为能够感测显著人类关节运动的可穿戴应变传感器,比如手腕弯曲,和涉及手腕的动作,手指,和肘部。同样,他们擅长监控人类微妙的动作,例如语音发音,区分不同的单词,以及在各种活动中检测吞咽和喉振动。除了这些应用,水凝胶在区分和再现各种书面单词方面表现出熟练的可靠性。基于Zn-MOF的水凝胶在电子皮肤中具有广阔的发展潜力,医疗监测,软机器人,和灵活的触摸面板。
Metal organic frameworks (MOFs) have garnered significant attention in the development of stretchable and wearable conductive hydrogels for flexible
transducers. However, MOFs used in hydrogel networks have been hampered by low mechanical performance and poor dispersibility in aqueous solutions, which affect the performance of hydrogels, including low toughness, limited self-recovery, short working ranges, low conductivity, and prolonged response-recovery times. To address these shortcomings, a novel approach was adopted in which micelle co-polymerization was used for the ex situ synthesis of Zn-MOF-based hydrogels with exceptional stretchability, robust toughness, anti-fatigue properties, and commendable conductivity. This breakthrough involved the ex situ integration of Zn-MOFs into hydrophobically cross-linked polymer chains. Here the micelles of EHDDAB had two functions, first they uniformly dispersed the Zn-MOFs and secondly they dynamically cross-linked the polymer chains, profoundly influencing the mechanical characteristics of the hydrogels. The non-covalent synergistic interactions introduced by Zn-MOFs endowed the hydrogels with the capacity for high stretchability, high stress, rapid self-recovery, anti-fatigue properties, and conductivity, all achieved without external stimuli. Furthermore, hydrogels based on Zn-MOFs can serve as durable and highly sensitive flexible
transducers, adept at detecting diverse mechanical deformations with swift response-recovery times and high gauge factor values. Consequently, these hydrogels can be tailored to function as wearable strain sensors capable of sensing significant human joint movements, such as wrist bending, and motions involving the wrist, fingers, and elbows. Similarly, they excel at monitoring subtle human motions, such as speech pronunciation, distinguishing between different words, as well as detecting swallowing and larynx vibrations during various activities. Beyond these applications, the hydrogels exhibit proficiency in distinguishing and reproducing various written words with reliability. The Zn-MOF-based hydrogels hold promising potential for development in electronic skin, medical monitoring, soft robotics, and flexible touch panels.