Orlando Rojas

Nanocelluloses: Natural Fiber Deconstruction and (Re)Essemblage to Engineer New Materials   Aalto University, Finland and NC State University, USA

Biography

Dr. Rojas, a chemical engineer by training, joined NC State in 2004 soon after completing tenures as postdoctoral associate and senior scientist appointed by the Royal Swedish Academy of Sciences in the Royal Institute of Technology (KTH, Sweden), in the Department of Chemistry, Surface Chemistry. He currently holds professor positions in Aalto University and NC State, in Forest Biomaterials and Chemical and Biomolecular Engineering. He was appointed Finland Distinguish Professor in Aalto University and was the Chair of the “Division of Cellulose and Renewable Materials” of the American Chemical Society (2009-2011). In 2013 he was selected as Fellow of the American Chemical Society for his scientific contributions. He was appointed as a “2013-2017 Faculty Scholar” of NCSU and received the “Cellulose and Renewable Materials” Division Fellow Award. His work is centered on the utilization of lignocellulosic materials in novel, high performance applications and the interfacial and the adsorption behaviors of surfactants and polymers at solid/liquid interfaces.  He has published more than 170 peer-reviewed papers and directs the Bio-based Colloids and Materials group (BiCMat) with 25 members between Aalto and NC State universities.

Abstract

We introduce our work related to the application of surface and colloid science in the development of cellulose-based materials. These efforts take advantage of the process by which nature assembles fibers in a highly hierarchical structure encompassing a wide range of sizes, from the nano to the meter scales. A number of materials cleaved from the cell wall have been the subject of intensive research, including, cellulose nanofibrils (CNF) and cellulose nanocrystals (CNCs), i.e., defect-free, high aspect ratio, semi-crystalline residues after chemical enzymatic and mechanical treatment. Interest in nanocelluloses originates from their appealing intrinsic properties: nanoscale dimensions, high surface area, unique morphology, low density, chirality and mechanical strength. Directing their assembly back to high-performance structures, including fibers, films, aerogels and multiphase systems is a quest that has yielded promising results for revolutionary applications. As such, we will discuss the use of non-specific forces to create functional materials including systems that are responsive to electrical, magnetic and piezoelectric stimuli. Assemblies at interfaces will be introduced as means to produce or stabilize composites, hydrogels, aerogels, and Pickering emulsions. Overall, the prospects of such novel materials will be explained in light of the unique properties of cellulose from natural fibers.