Facile Preparation of 3D Aerogels With Aligned Fibre Structure for Filtration Application

Abstract

3D fibre aerogels with aligned architecture, due to their high porosity, interconnected pore structure and high specific surface area, show great potential in sound absorption, oil-water separation and air filtration. Herein, we present a novel and simple long straight bundle electrospinning strategy inspired by Darwin's bark spider to prepare 3D aligned fibre aerogels. Different from the conventional electrospinning, whipping instability of the fibre is effectively eliminated by manipulating the distribution of electric field lines during the long straight bundle electrospinning, resulting in the formation of a 3D aligned fibre aerogel. The detailed long straight bundle electrospinning process (formation of fibre bundle, flying path of fibre bundle and deposition of fibre bundle) along with the underlying mechanism are systematically studied. Based on this theoretical basis, scalable fabrication of the 3D flexible aligned fibre aerogel with an ultrahigh fibre alignment degree of 0.93 and an ultrathick structure (2.8 cm) is achieved in one step. As a proof of concept, we investigate the use of the 3D aligned fibre aerogel in air filtration. It is found that the fibre aerogel shows excellent PM_1.0 and PM_2.5 filtration performance in both perpendicular to and parallel to fibre alignment direction. Interestingly, the pressure drop in the direction parallel to fibre alignment is only 21 Pa, which is much lower than that in the direction perpendicular to fibre alignment. We also compare the filtration performance of our 3D fibre aerogel with other filters and find that the comprehensive performance of our aerogel is obviously better.