Layer-by-layer self-assembled tubular films containing polyoxometalate on electrospun nanofibers

Abstract

Self-assembled polyoxometalate (H 3PMo 12O 40) ultrathin tubular films were fabricated on electrospun cellulose acetate (CA) nanofibers via the electrostatic layer-by-layer (LBL) adsorption of oppositely charged polyethylenimine (PEI) and H 3PMo 12O 40. The films coated fibers were characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and wide-angle X-ray diffraction (WAXD). The morphology of LBL films coated CA nanofibers was studied by regulating the pH value and ionic strength of PEI solutions, the number of PEI/H 3PMo 12O 40 bilayers, and the concentration of H 3PMo 12O 40. The results indicated that the growth of LBL films fabricated at a PEI pH of 2.5 and a H 3PMo 12O 40 pH of 2.5 (PEI2.5/H 3PMo 12O 402.5) was much quicker than that of films of PEI and H 3PMo 12O 40 adsorbed at pH 9 and 2.5 (PEI9/H 3PMo 12O 402.5), respectively. Moreover, the concentration of H 3PMo 12O 40, the number of coating bilayers, and the ionic strength of PEI solutions also showed strong influence to the growth of LBL films on nanofibers. Additionally, the high porous LBL films coated fibers were found after the deposition of PEI/H 3PMo 12O 40 films from a high ionic strength of PEI solutions.