Polyaniline doped with lignosulfonate (PANI/LGS) was prepared by using a facile oxidative polymerization of aniline with (NH4)2S2O8 as an oxidant, and the structure and morphology of PANI/LGS were investigated. As an active material for supercapacitors, the capacity retention rate of PANI/LGS was 75.1% with a growth of current density from 0.2 to 10 A g−1, indicating a high rate performance, and that of PANI was only 38.3%. For PANI/LGS, a specific capacitance of 377.2 F g−1 remained at 10 A g−1, and that of PANI was 183.7 F g−1. Moreover, the cycling stability was also measured in a two-electrode symmetrical capacitor at a current density of 1.0 A g−1. The capacity retention rate of PANI/LGS was 74.3% after 10 000 cycles, and that of PANI was 52.8%.
To confer cellulose fibers antimicrobial and antioxidant activities, chitosan (CS)/lignosulfonates (LS) multilayers were constructed on fibers surfaces through layer-by-layer deposition technique. The formation of CS/LS multilayers on cellulose fibers surfaces was verified by X-ray photoelectron spectroscopy (XPS) and zeta potential measurement. The surface morphologies of CS/LS multilayers on fibers surfaces were observed by atomic force microscopy (AFM). The results showed that characteristic element (i.e. N and S element) content increased with increasing bilayers number, the surface LS content increased linearly as a function of bilayers. Zeta potential of modified fibers was inversed after deposition of each layer. AFM phase images indicated that the cellulose microfibrils on fibers surfaces were gradually covered by granular LS aggregate. The antimicrobial testing results demonstrated that CS/LS multilayers modified fibers with CS in the outermost layer exhibited higher antimicrobial activity against Escherichia coli . The antioxidant testing results showed that antioxidant activity of CS/LS multilayers modified fibers was better than that of original fibers under the same oxidation conditions.