The 6th Glyco@Event will take place at LGP2 room D2 on Friday, December 15th from 10:30 to 12:30. The invited speaker is Emily D. Cranston, from McMaster University, Canada, who will give a talk on “Transforming Cellulose Nanocrystals into Sustainable Products through Surface Engineering”. Two young glycoscientists from Glyco@Alps, Johanna Desmaisons and Clémentine Darpentigny will kick off the event with short talks.

Invited speaker

Transforming Cellulose Nanocrystals into Sustainable Products through Surface Engineering

Emily D. Cranston, McMaster University, Canada

By learning from nature and using bio-based nanoparticles we can engineer sustainable high-performance materials with improved functionality. Cellulose nanocrystals (CNCs) are entering the marketplace as new ingredients for formulated chemical products. As “green” and potentially food-grade additives, there is widespread interest in CNCs particularly as emulsifiers, rheological modifiers, and reinforcing agents. We believe that the surface chemistry of CNCs must be well understood and controlled in order to elucidate the interactions, stability and compatibility of CNCs with liquids, polymers and small molecules.

I will present our recent benchmarking study of industrially produced CNCs and show applications of CNCs as (1) interface stabilizers in wet and dry oil/water emulsions; (2) property modifiers in synthetic latexes with a focus on improving pressure sensitive adhesives; and (3) mechanical enhancers in foams/gels. Specifically, CNC aerogels offer a flexible networked structure to support other functional nanomaterials which we have demonstrated as energy storage and water purification devices. This new understanding can be used to extend the capabilities of CNCs in food/cosmetic products, encapsulation technologies, coatings/adhesives, and tissue engineering scaffolds.

Biography: Emily D. Cranston is an Associate Professor in Chemical Engineering at McMaster University in Canada and holds the Tier 2 Canada Research Chair in Bio-Based Nanomaterials. Her research focuses on sustainable nanocomposites and hybrid materials from cellulose and other biopolymers. Her academic path began at McGill University where she received her Honours B.Sc. in Chemistry with bio-organic specialty and a PhD in Materials Chemistry in the group of Professor Derek Gray. The study of value-added products from cellulose took her to Stockholm, Sweden as a postdoctoral researcher at KTH Royal Institute of Technology before she returned to Canada in 2011. Emily is the recipient of the 2017 KINGFA Young Investigator’s Award from the American Chemical Society’s Cellulose & Renewable Materials division, is a Distinguished Engineering Fellow at McMaster University and will be the 2018 Kavli Foundation Emerging Leader in Chemistry Lecturer at the Spring ACS meeting in New Orleans.

Young scientists talks

Buckling-based metrology for measuring the Young’s modulus of polyvinyl alcohol – cellulose nanocrystals thin biocomposites.

Johanna Desmaisons, LGP2

Cellulose nanocrystals are rod-like and highly crystalline nanoparticles obtained after acid hydrolysis of cellulose fibre. In addition to their low density, high aspect ratio, high specific surface, and chemically reactive surface, this material is well known for its high stiffness and Young’s modulus. Thanks to these particular properties, cellulose nanocrystals can be used as very good reinforcing agent in nanocomposites within a wide variety of applications. Coating is one of the promising applications for nanocellulose composites mainly for barrier applications but also for rigid layer deposition.
Precise methods exist for determination of film mechanical properties. Among them, we count tensile test, dynamic mechanical thermal analysis or three points bending flexural tests. However, these methods are only feasable with thick free-standing films. It has been proved that coating processes modifies CNC organization in nanocomposites. To perfectly understand the effect of cellulose nanocrystals embedded in a polyvinyl alcohol matrix as a coating layer, a strain-Induced elastic buckling instability method has been studied and adapted. The principle of this method is to measure how a rigid material (the tested film) surface wrinkles when it is compressed on a soft substrate (PDMS). This recent method implemented by Stafford (Stafford et al. 2004) has been tried with thin film of nanocellulose composites or  (Cranston et al. 2011) in the case of layer by layer method with ultra-thin films corresponding to thicknesses of 35 to 75 nm. However, the adaptation of this method to bar coating systems with micrometrics layers is new and uncertain. In this study it is question to understand the buckling model limits and adaptation for simulate the mechanical properties of a paper coating layer. The second objectives are to study the influence of coating process, paper drying and amount of cellulose nanocrystals on these mechanical properties. First results are promising and clear influence of process parameters can be seen with using this new methodology.
 

Nanocellulose-based materials functionalized in supercritical carbon dioxide - Natural active  molecules grafted on bio-based and biocompatible materials for  antimicrobial wound dressings applications.

Clémentine Darpentigny, Cermav

In a context where the need for innovative medical devices is increasing and the environmental issue is becoming a priority, our objective is to develop “active” wound dressings with antibacterial and antifungal properties using a bio-inspired strategy. First, nanocellulose derived from the biomass are used as biocompatible building blocks. They are assembled to prepare aerogels or membranes with structural parameters controlled by the preparation process and the nanocellulose properties. The nanocellulose-based materials will then be functionalized in supercritical carbon dioxide in an attempt to respect green chemistry principles. The variety of nanocellulose structures will allow us to establish structure-functionalization-bioactivity relationship and optimize the design of bioactive wound dressings.