Photo-responsive electrospun polymer nanofibers: Mechanisms, properties, and applications

Photo-responsive polymers have attracted increasing attention due to the unique advantages that light stimulus provides, such as high sensitivity, precise selectivity, temporal and spatial control as well as its non-aggressive nature. Photo-responsivity can be divided into different categories including fluorescence and phosphorescence emission, photochromism, variable wettability and polarity changes, photocatalysis, photodynamic therapy, photo fluidization, photothermal function, photo-induced shape memory effects, and photo-locomotion. The chemical integration or physical doping of the photo-responsive compounds to a polymer matrix could induce such photo-responsivity to the host polymers. In recent years, electrospinning has been used as an effective method to fabricate photo-responsive electrospun nanofibrous mats with improved photo-responsive functionalities due to their porous structure with a high surface-to-volume ratio. This review focuses on the recent developments in photo-responsive electrospun polymer nanofibers. The preparation methods and electrospinning parameters, incorporated photo-responsive compounds, photo-responsive mechanisms, and the application areas of the photo-responsive electrospun nanofibrous mats are covered in detail. In this review, the recent studies on photo-responsive polymer nanofibers will be discussed and arranged based on their application types, such as monitoring and sensing, food packaging, anticounterfeiting, drug delivery, wound healing, bioactivity, membranes, and self-cleaning. Moreover, new strategies are proposed for each application field for the future studies to prepare multi-functional electrospun nanofibers with different morphologies, such as layer-by-layer, core-shell, and Janus nanofibers. It is believed that this review may provide new horizons in the preparation of new photo-responsive electrospun polymer nanofibers with smart applications.