Multi-site sulfonation of lignin for the synthesis of a high-performance dye dispersant.

Sulfonated lignin-based dye dispersants have intensively attracted attention due to their low cost, renewability and abundant sources. However, their utilization is limited by the low content of sulfonic groups and high content of hydroxyl groups in their complex lignin structure, which results in various problems such as high reducing rate of dye, severe staining of the fibers and uneven dyeing. Here, the multi-site sulfonated lignin-based dispersants were prepared with high sulfonic group content (2.20 mmol/g) and low hydroxyl content (2.43 mmol/g). When using it as the dispersant, the dye uptake rate was improved from 69.23 % to 98.55 %, the reducing rate was decreased from 20.82 % to 2.03 %, the K/S value was reduced from 0.69 to 0.02, and the particle sizes in dye system before and after high temperature treatment were stabilized below 0.5 µm. Besides, the dispersion effect was significantly improved because no obvious separation between dye and water was observed even if without the assistance of grinding process. In short, the multi-site sulfonation method proposed in this work could remarkably improve the performances of the lignin-based dye dispersants, which would facilitate the development of the dye dispersion and the high value utilization of lignin.

Concealed fluorescent anti-counterfeiting paper prepared by loading perovskite and lead-metal-organic framework on cellulose fibers.

Counterfeiting has caused great concern all over the world. What's more, the fluorescent materials play an important role in technological research and development for high-security. In this work, lead-metal-organic framework (Pb-MOF) and perovskite (MAPbBr3) were used in papers to achieving fluorescence counterfeiting. Pb-MOF, as the template or precursor of MAPbBr3, were in-situ generated on the surface of cellulose fibers (CFs) to preparing into hand sheets (Pb-MOF@CFs). Through the analysis of experimental results, it was found that ligands, reaction systems, addition sequences of drugs, time, etc. would affect the deposition of Pb-MOF on the surface of CFs. Using CH3NH3Br (MABr) as the anti-counterfeiting ink to write on Pb-MOF@CFs, the orange writing leaped across the paper, which caused by Pb in Pb-MOF chemically reacting with MABr forming MAPbBr3. The orange writing displayed green fluorescence under 365 nm ultraviolet lamp excitation. The orange writing with green fluorescence could be extinguished and reconstructed, which had promise for reuse. In addition, fluorescent security papers (MAPbBr3@Pb-MOFs@CFs) were prepared by immersing Pb-MOF@CFs in MABr solution. The fluorescence of MAPbBr3@Pb-MOFs@CFs opened when the surface of it was scraped under 365 nm ultraviolet lamp. This unique fluorescence property was very important in improving the security of products. Consequently, the ongoing research on perovskite and MOFs materials is of great significance.

Development of novel paper-based supercapacitor electrode material by combining copper-cellulose fibers with polyaniline.

Along with the developing of flexible electronics, there is a strong interest in high performance flexible energy storage materials. As natural carbohydrate polymer, cellulose fibers have potential applications in the area due to their biodegradability and flexibility. However, their conductive and electrochemical properties are impossible to meet the demands of practical applications. In this study, cellulose fibers were combined with polyaniline to develop novel paper-based supercapacitor electrode material. Cellulose fibers were firstly coordinated to Cu(II) and subsequently involved in polymerization of polyaniline. Not only the mass loading of polyaniline was significantly increased, but also an impressive area specific capacitance (2767 mF/cm2 at 1 mA/cm2) was achieved. The developed strategy is efficient, environmentally friendly, and has implications for the development of cellulosic paper-based advanced functional materials.

Innovative modification of cellulose fibers for paper-based electrode materials using metal-organic coordination polymers.

Cellulosic paper-based electrode materials have attracted increasing attention in the field of flexible supercapacitor. As a conductive polymer, polyaniline exhibits high theoretical pseudocapacitive capacitance and has been applied in paper-based electrode materials along with cellulose fibers. However, the stacking of polyaniline usually leads to poor performance of electrodes. In this study, metal-organic coordination polymers of zirconium-alizarin red S and zirconium-phytic acid are applied to modulate the polyaniline layer to obtain high-performance cellulosic paper-based electrode materials. Zirconium hydroxide is firstly loaded on cellulose fibers while alizarin red S and phytic acid are introduced to regulate the morphology of polyaniline through doping and coordination processes. The results show that the introduction of dual coordination polymers is effective to regulate the morphology of polyaniline on cellulose fibers. The performances of the paper-based electrode materials, including electrical conductivity and electrochemistry, are apparently improved. It provides a promising strategy for the potential development of economical and green electrode materials in the conventional paper-making process.

High mass loading paper-based electrode material with cellulose fibers under coordination of zirconium oxyhydroxide nanoparticles and sulfosalicylic acid.

With the rapid expansion of the flexible electronics market, it is critical to develop high-performance flexible energy storage electrode materials. Cellulose fibers, which are sustainable, low cost, and flexible, fully meet the requirements of flexible electrode materials, but they are electrically insulating and cause a decrease in energy density. In this study, high-performance paper-based flexible electrode materials (PANI:SSA/Zr-CFs) were prepared with cellulose fibers and polyaniline. A high mass loading of polyaniline was wrapped on zirconia hydroxide-modified cellulose fibers under metal-organic acid coordination through a facile in situ chemical polymerization process. The increase in mass loading of PANI on cellulose fibers not only improves the electrical conductivity but also enhances the area-specific capacitance of the flexible electrodes. The results of electrochemical tests show that the area specific capacitance of the PANI:SSA/Zr-CFs electrode is 4181 mF/cm2 at 1 mA/cm2, which is more than two times higher than that of the electrode with PANI on pristine CFs. This work provides a new strategy for the design and manufacture of high-performance flexible electronic electrodes based on cellulose fibers.

Design and fabrication of high performance supercapacitor with cellulosic paper electrode and plant-derived redox active molecules.

As a promising substrate, cellulose fibers were widely investigated in supercapacitors for their low cost and sustainability. However, the low performance created great barrier for the future applications of the cellulosic paper-based supercapacitors. The performance of paper-based supercapaciors may be improved by the addition of redox active molecule. As a plant derived redox active molecule, Alizarin red S was used to improve the performance of PEDOT paper-based electrode via a simple post-treatment process. By combination of the treated paper electrode and the redox electrolyte, a symmetric paper-based supercapacitor with a superior performance of 2191.3 m F/cm2 (at 5 mA/cm2) and 4.87 mW h/cm3 (at power density of 36 mW/cm3) were fabricated. The charge and mass transfer mechanisms of paper electrode were detailed discussed. The simple and efficient strategy developed in this work opens up new doors for the development of other cellulose related high performance energy storage devices.

High mass loading polyaniline layer anchored cellulose fibers: Enhanced interface junction for high conductivity and flame retardancy.

Novel cellulose fibers-based composite consisted of zirconium oxyhydroxide and phytic acid doped polyaniline was prepared via a two-step method of simple chemical precipitation and followed by in situ polymerization process. Cellulose fibers were firstly modified with zirconium oxyhydroxide to enhance the binding of phytic acid doped polyaniline to the surface. A compact coating of phytic doped polyaniline was developed on zirconium oxyhydroxide modified cellulose fibers through the chelating of zirconium ions to phytic acid. The resulting composite possessed a controllable mass loading of polyaniline, which could significantly improve the conductivity, flame retardancy and electrochemical stability. Therefore, the expected chelating between zirconium ions on cellulose fibers and phytic acid doped in polyaniline supported the excellent properties of the composite paper. Notably, the developed strategy is efficient, low-cost and environmental friendly, and the work opens up new doors to the development of other cellulose fibers-related interface enhancement applications.