Formation and self-assembly of 3D nanofibrous networks based on oppositely charged jets

•A novel technique for creating 3D nanofibrous networks on a large scale was proposed.•This novel methodology based on oppositely charged jets with controlled upward airflow•The sizes and morphologies of artificial 3D nanofibrous networks can be well-controlled.•Nontrivial improvement of sound absorption in the audible frequencies were observed.

Three-dimensional (3D) porous materials with nano/μ structured fibre-fibre interactions are promising candidates for tissue engineering scaffolds, material separation diaphragms, energy storage and dissipation systems, and catalyst materials, etc. However, the conventional electrospinning process is mainly focused on the surface depositions of 2D nanofibrous mats. In this work, we propose a novel methodology of creating 3D nanofibrous networks, featured with neutralization and self-assembly of electrospun nanofibers by means of dual electrospinning from oppositely charged polymer jets. Using a fine-tuned upward airflow from a controllable heat source, we have successfully counterbalanced the gravity as well as the electrostatic force acting on the inflated intertwined jets clusters, which permits the mass production of 3D nanofibrous materials. We also experimentally measured sound absorption coefficients of the 3D nanofibrous networks in a standing wave tube and observed a nontrivial improvement of sound absorption in the audible frequencies ranging from 400 to 900 Hz by comparing with commercial muffler materials.

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