Morphology engineering of protein fabrics for advanced and sustainable filtration

The high removal efficiency, low flow resistance, high filtration capacity of pollutants and the capability of removing different types of pollutants are critical for advanced air-filters. However, it has been very challenging to simultaneously realize these performances for traditional filtering materials. Herein, we report a study on the development of a new strategy for the fabrication of multi-functional protein fabrics with novel ribbon morphology and cotton-candy-like structures to address the above challenges. In particular, a metastable solution of zein protein in a solvent mixture is proposed for the first time to fabricate the ribbon-like fibres with self-curving behaviour. This self-curved zein fabric has multiple significant contributions to filtration. Firstly, the ribbon morphology notably enhances the trapping capability for sub-micron particulate pollutants in particular. Secondly, the self-curving feature of the fibres generates cotton-candy-like loose structures and elastic properties for the fabric, which significantly reduces the flow resistance. As a result, the filtration performances have been simultaneously improved, including enhanced capture efficiency, filtration capacity and stability of air pressure drop, as well as the reduced airflow resistance, as compared with traditional fabrics with rod-shaped fibres. This study does not only provide a new electrospinning strategy for the fabrication of functional ribbon-like fibres but also presents guidelines for the design of advanced fabrics for various filtration applications.