Cellulose represents a substantial raw material resource in future industrial production and can contribute to the future circular economy and sustainable development of our society. In recent years, the dissolution and regeneration strategies of cellulose have been a subject of significant research interest. Understanding the microscopic mechanisms of regeneration of cellulose is prerequisite for engineering and controlling its material properties. However, due to the limitations of all-atom simulations, previous studies can hardly represent and describe the experimentally regenerated cellulose morphologies. Thus, for a realistic description of the cellulose regeneration process, coarse-grained (CG) MD simulations need to be developed and applied.

In this paper, we performed coarse-grained Martini 3 molecular dynamics simulations of cellulose regeneration at a scale comparable to the experiments. The X-ray diffraction (XRD) curves were monitored to follow the structural changes of regenerated cellulose and trace formation of cellulose sheets and crystallites. The calculated coarse-grained morphologies of regenerated cellulose were backmapped to atomistic ones. After the backmapping we find that the regenerated coarse-grained cellulose structures calculated for both topology parameters of cellulose-Iβ and cellulose II/III, are transformed to cellulose II, where the calculated XRD curves exhibit the main peak at approximately 20-21 degrees, corresponding to the 110/200 planes of cellulose II. This result is in good quantitative agreement with the available experimental observations.