Cellulose nanofibrils are the major constituents of plant cell walls. NFCs can be extracted from native cellulosic fibers using various chemical and mechanical treatments. The slender shape, high mechanical strength make them a promising building block for structural or functional materials as green composites, films, foams or aerogels.
The project focuses on the elastic mechanical properties of NFC suspensions. First the elementary mechanical properties of cellulose crystals are studied at the atomic scale using molecular dynamics. Then the gathered mechanical response is homogenized and implemented at the meso-scale in the so-called discerete elastic rod method.
Finally, the complex network of the individual NFC rods are going to be modelled to determine the elastic stiffness tensor of an NFC suspension. These results are then compared to real life rhonometry experiments.
The project is conducted at 3SR laboratory in Grenoble under the leadership of Orgéas Laurent in collaboation with David Rodney (ILM), Karim Mazeau, Yoshiharu Nishiyama (Cermav), Pierre Dumont and Florian Martoïa (INSA de Lyon).
Elementary shear mechanism of cellulose crystals
In the first stage of the study, bulk atomic structures were deformed in three different direction. The following movies illustrate the elementary mechanisms controlling the stress response of the samples. More about the topic can be found here.