摘要

The secondary structure of different I beta cellulose was analyzed by a molecular dynamics simulation with MARTINI coarse-grained force field, where each chain of the cellulose includes 40 D-glucoses units. Calculation gives a satisfied description about the secondary structure of the cellulose. As the chain number increasing, the cellulose becomes the form of a helix, with the diameter of screw growing and spiral rising. Interestingly, the celluloses with chain number N of 4, 6, 24 and 36 do show right-hand twisting. On the contrast, the celluloses with N of 8, 12, 16 chains are left-hand twisting. These simulations indicate that the cellulose with chain number larger than 36 will break down to two parts. Besides, the result indicates that 36-chains cellulose model is the most stable among all models. Furthermore, the Lennard-Jones potential determines the secondary structure. In addition, an equation was set up to analyze the twisting structure.