Mini symposium : "Workshop on Nanocellulose Characterization: AFM & Rheology"

9:30 - 10:20 Kazuho Daicho (Assistant Professor, School of Engineering, U. Tokyo, orcid: 0000-0003-4203-2257)
Title: Surface charged groups of nanocellulose visualized by frequency-modulation atomic force microscopy
Abstract: The finest type of nanocellulose (NC) possesses ionic functional groups on the fibril surfaces, such as carboxylate and phosphate groups. These functional groups work as reaction points for further functionalization of NC. Although these surface functional groups have been quantified by various methods, their two-dimensional distributions are still unrevealed. 
Frequency-modulation atomic force microscopy (FM-AFM) is able to visualize the hydration structure of solid surfaces by the detection of a force between the tip and sample as a frequency shift value.
In this study, we aimed to map the ionic functional groups on the NC surface by hydration structure analysis of FM-AFM. I would like to introduce our recent results in this seminar.

10:30 - 11:20 Tomoki Ito (PhD candidate, School of Agr. & Life Science, U. Tokyo, orcid:  0000-0002-2473-7117)

Title: Local Structures of Cellulose Nanofibers
Abstract: Cellulose Nanofiber (CNF), a nanomaterial derived from wood, has been attracting attention as a highly functional material in a low-carbon society due to its various superior properties. Numerous local structures including bending points, splits, and thin fragments in CNF have been identified through observations via Atomic Force Microscopy (AFM), and these structures significantly influence the material properties of CNF. However, the analysis of AFM images has typically been conducted manually, making the quantitative analysis of CNF’s local structures challenging. In this study, we engaged in a detailed analysis of CNF morphology utilizing image processing techniques to elucidate the shape, distribution, and the formation mechanisms of CNF’s local structures.
 

11:30- 12:20 Lise  Morlet—Decarnin (PhD candidate, laboratoire de physique, ENS Lyon, https://www.researchgate.net/profile/Lise-Morlet-Decarnin)

Title: Cellulose nanocrystals: from gels to solid materials
Cellulose nanocrystals (CNC) are solid rod-like particles that bear a negative surface charge. Once suspended in salty water, they aggregate to form a gel with remarkable mechanical and optical properties. Such a gel can serve as a precursor to the design of solid materials, to which it may transmit part of its mechanical properties. The goal of this work is first to understand the rheological behavior of CNC gels, from their formation to their rupture, and link it to the internal microstructure of the gel. Second, I will examine how mechanical and/or structural properties may be transmitted to the solid material through solidification by drying or freezing.