MSE Seminar Series: Lina Zhang, Wuhan University
Speaker: Lina Zhang, Distinguished Professor of Chemistry and Molecular Sciences, Wuhan University, China
Title: Novel functional materials fabricated from natural polymers via "green" process
Faced with the serious challenge of “Environmental Protection and Sustainable Development”, we have developed a new route to fabricate novel functional materials derived from the renewable natural polymers by using low-cost chemical reagents and environmentally friendly process. Our innovative solvents such as NaOH/ urea aqueous solution have been used successfully to dissolve cellulose, chitin and polyaniline (PANI) at low temperature, resulting in a transparent solution. The dissolution at the low temperature was a typical enthalpy-driven process, and was mainly a physical method. The results of SLS, DLS and AFM indicated that an extended wormlike chain conformation of cellulose or chitin/chitosan exists in the dilute solution, and the nanofibers could be constructed from them in parallel aggregation in the aqueous solution. From the cellulose, chitin and/or chitosan solutions in the alkali/urea aqueous system, the regenerated materials including fibers, films, microspheres, plastics, hydrogels and aerogels have been fabricated. Interestingly, highly strong multifilament fibers with nanofibril structure were spun successfully from the cellulose and/or chitin solutions in the alkali/urea aqueous system on a small pilot wet-spinning machine. These fibers consisted of the nanofibers, and exhibited excellent mechanical properties with high tensile strength ( 3.5 cN/dtex for cellulose fibers and 2.5 cN/dtex for chitin fibers). Moreover, these functional materials fabricated directly from the cellulose solution, chitin or chitosan solutions, cellulose/ PANI solution via physical regenerated methods exhibited excellent mechanical properties, efficiently self-healable ability, sensitively force-response，magnetic-induced delivery, the good electrochemistry properties & high discharge capacity, the excellent biocompatibility and the cells adhesion and proliferation viability etc, and their relationship of structure to properties was revealed. These materials are believed to have promising applications in biomedical, energy storage, wastewater treatments and textile manufacturing that will lead to the implementation of a (future) sustainable society. Therefore, we open up a completely new avenue to construct novel materials based on the natural polymers via a “green” process, leading to the promising wide applications.
Acknowledgements This work was supported by the Major Program of National Natural Science Foundation of China (21334005) and the Major International (Regional) Joint Research Project of National Natural Science Foundation of China (21620102004).