Abstract
ABSTRACT This paper reports computer simulations (accompanied by nanoscale measurements) performed in order to understand the molecular mechanism of the polarization switching in the polyvinydilene flurouride and its copolymer with trifluoroethylene [P(VDF-TrFE)], using quantum-chemical methods based on the HyperChem 7.5 software. The simulated data for P(VDF-TrFE) were calculated for different copolymer contents (70:30), (60:40) and for pure PVDF. The calculated values of the dipole moment and average polarization of the molecular chains show well defined hysteresis under varying electric field with polarization saturated at known data ∼0.1…0.14 C/m2. The calculated coercive fields (for model of the rotation of molecular chains) are consistent with experimental data for thin P(VDF-TrFE) (70:30) films, prepared by Langmuir-Blodgett (LB) technique (E c = 5–18 MV/cm). The piezoresponse force microscopy (PFM)) measurements of the local hysteresis loop (at fixed tip position) at same LB samples demonstrated clear ferroelectric switching. The molecular dynamic simulation performed by HyperChem 7.52 tool for the molecular model of 4 free polymer chains slab provides very fast rotation (relaxation) time ∼0.4 ps. The analysis show that this model is most close to thick LB films, while in thin LB films the strong electrostatic dipole interaction with substrate must be taken into account.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
