Defect-Modified Ferroelectric Poly(vinylidene fluoride) Based Tetrapolymers

PART 1: NON-TECHNICAL SUMMARYFerroelectric polymers are a family of crystalline polymers having a net electric polarization that can be switched by an external electric field. Their utility spans various domains including solid-state cooling, soft robotics, haptic devices, artificial muscles, flexible memory, and high-energy-density capacitors. This project will deepen our understanding of the crystalline structures in ferroelectric polymers and impact of these structures on the physical properties. The success of this project will lead to new approaches to manipulating the polarization behaviors of the ferroelectric polymers. Additionally, this project seeks to establish scientific guidelines for designing ferroelectric polymers for next-generation environmentally friendly cooling technologies. The educational component of the project will involve training of students at all levels in emerging areas of electroactive polymers. The program includes research experiences with a focus on the recruitment and retention of underrepresented minorities in polymer science. Students working on this research project will gain valuable skills in interdisciplinary fields of polymers and applied physics. PART 2: TECHNICAL SUMMARYThe incorporation of chemical defects into ferroelectric polymers has proven its effectiveness of tailoring the polarization responses and ferroelectric behaviors of the polymers. The project will 1) develop an understanding of the crystalline structures and chain conformations of the ferroelectric polymers with chemical defects in the crystalline domains; 2) investigate the impact of the defect-modified crystalline structure on the polarization, ferroelectric properties and the electrocaloric responses of the ferroelectric polymers; and 3) establish fundamental understandings to enable rational design of ferroelectric polymers with high electrocaloric performance and new ferroelectric properties induced by defects in the crystal domains. The proposed research is anticipated to generate marked changes in the crystal structures and the ferroelectric properties that are unobtainable from the current ferroelectric polymers with bulky comonomers located at the crystalline/amorphous interface. Knowledge generated within this project will allow us to establish a new approach to ferroelectric polymers exhibiting tailorable ferroelectric properties and high electrocaloric performance. The program includes research experiences with a focus on the recruitment and retention of underrepresented minorities in polymer science..This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.