Fig. 4
From: Robust thermoelastic microactuator based on an organic molecular crystal
Molecular dynamics simulations. Molecular dynamic simulations show that the molecular configuration rearrangement by rotations of the dihedral angles (c, d) is accompanied by a change in cell dimensions (b) and crystal corner angle (a). Colored lines in the panels c and d correspond to a few individual molecules; one from each layer in the simulation cell. The black line follows the average over all 512 molecules (1024 dihedrals). The vertical dashed lines indicate the times at which the temperature in the simulation is changed from 27 °C via a linear ramp (between 60 and 160 ps) to 177 °C. The background colors visualize this temperature increase from blue to red. The outside colored short lines on the left and right borders of the graphs are the corresponding experimental values of the α-phase (at 27 °C) and β-phase (at 177 °C), respectively. Cooling the thus obtained structure to 27 °C shows that the energy of this new form is higher than that of the α-phase at the same temperature, making it indeed a reversible transition driven by entropy. Source data are provided as a Source Data file
