Synthesis of aramid nanoscale fiber-based nanocomposite with transparency, flexibility, and selective adsorption capability

Aramid nanofiber (ANF) has been regarded as an emerging excellent building block for preparing multifunctional high-performance composites, which are suitable for many applications in various fields. Based on this, for the first time, nanoscale bacterial cellulose (NBC) is used to modify ANF membrane via a direct blending followed with vacuum filtration. The chemical and physical structures of the NBC/ANF composite hybrid membranes (BAFM) are characterized by using Fourier transform infrared, X-ray diffraction, transmission electron microscope, and scanning electron microscope, demonstrating that NBC is well-dispersed into the ANF matrix. The two kinds of nanofibers twine together and interact with each other through hydrogen bonds, so that the tensile strength is enhanced from approximately 202–260 MPa by the incorporation of NBC. Besides, it is notable that the transparency retains due to the nanoscale diameter (much smaller than light wavelength) of the nanofibers, and the flexibility of the membranes is improved. Furthermore, the measurement of wettability shows that the hydrophilicity of the composite membranes could be improved by the addition of NBC, and the static water contact angle decreases from 85.6° to 63.5°. The adsorption process toward cationic (methylene blue, MB) and anionic (methyl orange, MO) dyes are preliminarily investigated, respectively. Due to the negatively charged ANF and the hydrophilic NBC, the BAFM exhibits selective adsorption ability toward MB, and the capacity could be improved by increasing the amount of NBC. Therefore, NBC is a desirable modifier for ANF to fabricate the composite, which is a promising candidate for transparent, flexible membranes with selective adsorption capacity.