Electro-spray deposited TiO 2 bilayer films and their recyclable photocatalytic self-cleaning strategy

Recyclable titanium dioxide (TiO 2 )-based photocatalytic self-cleaning films (SCFs) having a bilayer structure were prepared and assessed. These SCFs comprised two layers of fibers fabricated using an electrospinning process. The self-cleaning layer was made of acrylonitrile–butadiene–styrene (ABS) fibers with embedded TiO 2 while the substrate layer was composed of fibers made by simultaneously electrospinning poly (vinyl alcohol) (PVA) and ABS. This substrate improved the mechanical strength of the SCF and provided greater adhesion due to the presence of the PVA. The experimental results showed that the hydrophobicity (as assessed by the water contact angle), photocatalytic properties and self-cleaning efficiency of the SCF were all enhanced with increasing TiO 2 content in the ABS/TiO 2 fibers. In addition, the introduction of the substrate layer allowed the SCFs to be applied to various surfaces and then peeled off when desired. The ABS fibers effectively improved the strength of the overall film, while deterioration of the ABS upon exposure to UV light was alleviated by the addition of TiO 2 . These SCFs can potentially be recycled after use in various environments, and therefore have applications in the fields of environmental protection and medical science.