Qi Zhou

Biomimetic functional materials based on cellulose and chitin nanofibers   Associate Professor in the Division of Glycoscience, School of Biotechnology at Royal Institute of Technology (KTH), Sweden

Biography

Qi Zhou is currently Associate Professor in the Division of Glycoscience, School of Biotechnology at Royal Institute of Technology (KTH), Sweden. He joined KTH in 2002 after receiving a Ph.D. from the Department of Chemistry at Wuhan University, China. He has been a principal investigator in Swedish Center for Biomimetic Fiber Engineering (Biomime) and Wallenberg Wood Science Center (WWSC) at KTH. Biomime is a multidisciplinary Center of Excellence with cutting edge expertise at every level of the formation, modification and industrial utilization of wood, fibers and their constituent polymers. WWSC is a research center with a focus on new materials from trees. Qi’s group specializes in bio-based nanocomposites with multi-functionalities and well-defined structures, using wood nanocelluloses, chitin nanofibers, and native and modified carbohydrate polymers. The research strategy of his group allows a high level of integration of polymer synthesis and processing, chemo-enzymatic modification, and supramolecular assembly as inspired by natural materials such as wood cell wall, lobster cuticle, and nacre.

Abstract

An emerging field in biomimetics is bio-inspired nanostructure engineering which aims at using low-energy methodologies in order to considerably expand the range of properties of composite materials. The hierarchical structure presented in plant cell walls and lobster cuticle provides excellent biomimetic models for the fabrication of advanced composite materials based on cellulose and chitin nanofibers, the new building blocks of nanotechnology. In plant cell walls, cellulose I microfibrils are aligned and bound together into fibril aggregates by a matrix of hemicellulose and either pectin or lignin. In lobster cuticle, long crystalline a-chitin nanofibrils are individually wrapped with proteins and clusters to form chitin–protein fibers which are aligned in a mineral–protein matrix.
In this presentation, I will discuss our recent developments on biomimetic approaches applied to the design of cellulose and chitin nanofibers-based functional materials. To begin with, I will introduce the in-situ preparation of cellulose-based nanocomposite materials with high-strength and bactericidal activities using bacterial cellulose. Then, I will present the preparation of macroscopic ribbons of oriented cellulose nanofibrils as inspired by the plant cell walls. The cellulose nanofibrils are either grafted with a soft polymer, i.e. polyethylene glycol, or adsorbed with a hemicellulose, i.e. xyloglcuan. I will discuss the structure-property relationship – in particular that between the nanofibrils alignment and their mechanical and optical properties. Finally, I will present the preparation and properties of bio-inspired chitin/protein nanocomposites using chitin nanofibers and recombinant chitin-binding resilin.