Preparation and characterization of self-assembled polyelectrolyte multilayered films on electrospun nanofibers

Self-assembled polyelectrolyte multilayered (PEM) films were fabricated on electrospun cellulose acetate (CA) nanofibers via the electrostatic layer-by-layer adsorption of oppositely charged poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA). The growth of PEM films on CA nanofibers was studied by regulating the pH value of polyelectrolyte solutions and the number of PAH/PAA bilayers. The composition and morphology of PEM films coated fibrous mats were examined by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and atomic force microscopy. The results indicated that the growth of PEM films fabricated at a PAH pH of 7.5 and a PAA pH of 3.5 (PAH7.5/PAA3.5) was much quicker than that of films of PAH and PAA adsorbed at pH 5 (PAH5/PAA5). The CA nanofibers were embedded in the thick PAH7.5/PAA3.5 films. The average diameter of PAH5/PAA5 films coated fibers and average PAH5/PAA5 film thickness gradually increased with increasing the number of PEM bilayers. Moreover, the surface roughness of fibers was increased after deposition of PAH/PAA films.