双网络MXene水凝胶的制备及其电磁和紫外屏蔽性能

Preparation of dual-network MXene hydrogels and their electromagnetic and UV shielding properties

  • 摘要: MXene因其高导电性、丰富的活性位点(如—OH、—F、—O)、电化学行为和优异的亲水性使其在柔性可穿戴材料中显示出了特有的优势。然而,兼具优异力学强度和高电磁屏蔽效能的水凝胶还有待进一步研究;同时,透明水凝胶往往缺乏过滤紫外线的能力,这极大限制了材料的应用。本文以丙烯酰胺(AAm)共聚甲基丙烯酸羟乙酯(HEMA)化学交联为第一网络,聚丙烯酸(PAA)-Fe3+金属离子络合为第二网络,二维MXene作为导电纳米填料,制备了独特双屏蔽机制 PAAm-PHEMA/PAA-Fe3+-MXene水凝胶。MXene和Fe3+的存在使得该水凝胶同时兼具电磁和紫外屏蔽特性。通过 FTIR、SEM和EDS确认了水凝胶三维网络结构。所制备的双网络水凝胶具有高力学强度(320.1 kPa)、高拉伸性(1786%)和良好的导电性(3.8 S/m)。此外,该水凝胶还表现出了优异的紫外线屏蔽能力,在365和550 nm的特征波长下的透射率分别为0%和79.2%。同时,该水凝胶在X波段内可以获得超过 36 dB 的出色电磁屏蔽(EMI)效能以及对各种基材强黏附性、快速自愈合能力和高度形状适应性。本文提供了一种灵活且可高度可调的双屏蔽机制水凝胶网络设计和大规模简易制备新思路,在柔性可穿戴材料方面展示出了巨大的应用前景。

     

    Abstract: MXenes show unique advantages in electromagnetic shielding materials due to their high electrical conductivity, abundant active sites (such as —OH, —F, —O), electrochemical behavior, and excellent hydrophilicity. However, hydrogels with both excellent mechanical strength and high electromagnetic shielding efficiency remain to be further studied. Meanwhile, transparent hydrogels often lack the ability to filter ultraviolet light, which greatly limits the application of hydrogel materials. In this work, PAAm-PHEMA/PAA-Fe3+-MXene hydrogels with double shielding mechanism were prepared by using acrylamide (AAm) copolymer hydroxyethyl methacrylate (HEMA) chemical cross-linking as the first network, and polyacrylic acid (PAA)-Fe3+ metal ion complexation as the second network, and two-dimensional MXene as conductive nanofillers. The presence of MXene and Fe3+ makes the hydrogel possess both electromagnetic and UV shielding properties. The structure and three-dimensional network of the composite hydrogel were confirmed by FTIR, SEM and EDS. The as-prepared double-network hydrogel exhibits high mechanical strength (320.1 kPa), high stretchability (1786%), and good electrical conductivity (3.8 S/m). In addition, the composite hydrogel also exhibits excellent UV shielding ability, with transmittances of 0% and 79.2% at characteristic wavelengths of 365 and 550 nm, respectively. At the same time, the composite hydrogel can obtain excellent electromagnetic-interference (EMI) shielding effect of more than 36 dB in the X-band, strong adhesion to various substrates, rapid self-healing performance and high shape adaptability. This work provides a flexible and highly tunable dual-shielding mechanism hydrogel network design and large-scale facile fabrication of new ideas, showing great application prospects in flexible wearable materials.

     

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