Large-scale fabrication of highly aligned poly(m-phenylene isophthalamide) nanofibers with robust mechanical strength

Creating a facile and efficient method that can provide large-scale, highly aligned, and high strength nanofibers has proved extremely challenging. This work responds to these challenges by designing and evaluating poly(m-phenylene isophthalamide) (PMIA) nanofibrous materials with robust mechanical strength, which can be fabricated on a large scale via a facile combination of relative humidity (RH)-regulated electrospinning and multi-level aggregate reconstructing. The morphology and structure of the PMIA membranes can be finely controlled by regulating the solution concentration and RH during spinning, and a possible RH-regulated alignment mechanism was proposed. Additionally, PMIA nanofibrous aggregates of yarns and subsequent plaits were built up by multi-level reconstructing. During the first-level reconstructing based on twisting, the structure and mechanical properties of the yarns can be facilely optimized by tuning the twist level, and the PMIA yarns with 3000 TPM possess robust tensile strength of 262 MPa. The second-level reconstructing based on yarns braiding endows the corresponding nano-plaits with the highest tensile strength of 330 MPa. This novel method provides a new insight into the design and development of highly aligned nanomaterials for various applications.