Functional molecules surface segregation engineering in electrospinning: Design, regulation, and applications

Electrospinning has garnered significant attention for fabricating functional composite fibers. Recently, surface segregation exhibits great potential in shaping functional surface of fibers due to the ability to impart surface compositions different from those in the bulk phase. Moreover, the segregation behavior could be effectively regulated by altering the components' properties and the process designs, generating various functional composite electrospun fibers with controllable morphologies and superior performance. Despite the ongoing development and various applications of surface segregation electrospun fibers, surface segregation engineering in electrospinning has not been reviewed by far. To address this gap, this review presents the state-of-the-art developments of the functional molecules surface segregation engineering in electrospinning. Firstly, surface segregation phenomenon and the combination with electrospinning is presented. Secondary, process design and regulation methods of surface segregation during the whole electrospinning process are illustrated. Thirdly, characterization methods revealing the occurrence and extent of the surface segregation are comprehensively summarized. Finally, application of surface segregation electrospun fibers in prevalent fields such as gas sensing, separation and purification, superhydrophobization, anti-bacteria and biocompatibility improvement is discussed. We also highlight the challenges and further perspectives of the surface segregation engineering in electrospinning. This review aims to provide a comprehensive understanding and serve as a guide for future research and innovation in the design and application of functional molecules' surface segregation in electrospun fibers.