Studies of Effects of External Electric Field on Isolated and Crystalline Furan-derived Nanothread and PVDF through ReaxFF Method

Furan nanothreads have recently been synthesized through pressure-induced polymerization of molecular furan at room temperature. Its lower onset reaction pressure of about 10 GPa enables the scalability of synthesis and facilitates experimental measurements that require large quantity of samples. Furan threads promises to have intriguing electric properties owing to the polarity of the precursor coupled with a relatively rigid backbone. In order to investigate the response of external electric field applied on furan threads, we re-optimized the Chenoweth et al. C/H/O/ combustion ReaxFF reactive force field by extending the training set to include the thread oligomer bending property and the specific atomic net charge of furan thread. The reaction barrier of the furan dimer, and dipole moment of furan thread calculated using the re-trained force field agree well with that from DFT calculations. Comparing with an organic ferroelectric polymer with a flexible backbone, like a PVDF single chain, we find that isolated furan thread twists toward the electric field direction and generate larger torque with respect to the anchored end during to its rigid backbone. Both the randomly packed furan threads and PVDF can be poled by a moderate electric field at 50 K. These theoretical results predict unique physical responses for these novel furan threads which help inspire experimental measurement in the future.