Sir Lawrence Wackett Aerospace Research Centre, School of Engineering, RMIT University , GPO Box 2476, Melbourne, VIC 3001, Australia.
School of Mechanical and Manufacturing Engineering, University of New South Wales , Sydney, NSW 2052, Australia.
ACS Appl Mater Interfaces. 2017 Apr 26;9(16):14207-14215. doi: 10.1021/acsami.7b00847. Epub 2017 Apr 17.
Highly flexible and deformable electrically conductive materials are vital for the emerging field of wearable electronics. To address the challenge of flexible materials with a relatively high electrical conductivity and a high elastic limit, we report a new and facile method to prepare porous polydimethylsiloxane/carbon nanofiber composites (denoted by p-PDMS/CNF). This method involves using sugar particles coated with carbon nanofibers (CNFs) as the templates. The resulting three-dimensional porous nanocomposites, with the CNFs embedded in the PDMS pore walls, exhibit a greatly increased failure strain (up to ∼94%) compared to that of the solid, neat PDMS (∼48%). The piezoresistive response observed under cyclic tension indicates that the unique microstructure provides the new nanocomposites with excellent durability. The electrical conductivity and the gauge factor of this new nanocomposite can be tuned by changing the content of the CNFs. The electrical conductivity increases, while the gauge factor decreases, upon increasing the content of CNFs. The gauge factor of the newly developed sensors can be adjusted from approximately 1.0 to 6.5, and the nanocomposites show stable piezoresistive performance with fast response time and good linearity in ln(R/R) versus ln(L/L) up to ∼70% strain. The tunable sensitivity and conductivity endow these highly stretchable nanocomposites with considerable potential for use as flexible strain sensors for monitoring the movement of human joints (where a relatively high gauge factor is needed) and also as flexible conductors for wearable electronics (where a relatively low gauge factor is required).
高度灵活和可变形的导电材料对于新兴的可穿戴电子产品领域至关重要。为了解决具有相对较高电导率和高弹性极限的柔性材料的挑战，我们报告了一种新的简便方法来制备多孔聚二甲基硅氧烷/碳纳米纤维复合材料（表示为 p-PDMS/CNF）。该方法涉及使用涂覆有碳纳米纤维（CNF）的糖颗粒作为模板。所得的具有三维多孔纳米结构的复合材料，其 CNF 嵌入 PDMS 孔壁中，与固体、纯 PDMS（约 48%）相比，断裂应变大大增加（高达约 94%）。在循环拉伸下观察到的压阻响应表明，独特的微观结构为新的纳米复合材料提供了优异的耐久性。这种新纳米复合材料的电导率和应变系数可以通过改变 CNF 的含量来调节。随着 CNF 含量的增加，电导率增加，而应变系数减小。新开发的传感器的应变系数可以从大约 1.0 调整到 6.5，并且纳米复合材料在 ln(R/R) 与 ln(L/L) 的关系中表现出稳定的压阻性能，直到应变约 70%时具有快速响应时间和良好的线性度。可调的灵敏度和电导率使这些高可拉伸的纳米复合材料具有作为用于监测人体关节运动的柔性应变传感器（需要较高的应变系数）以及作为用于可穿戴电子产品的柔性导体（需要较低的应变系数）的巨大潜力。
