Strong impact of LiNbO3 fillers on local electromechanical and electrochemical properties of P(VDF-TrFe) polymer disclosed via scanning probe microscopy


Ivanov M. S., Silibin M., Khomchenko V. A., Nikitin T., Kalinin A. S., Karpinsky D., ...Daha Fazla

APPLIED SURFACE SCIENCE, ss.1093-1100, 2019 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1016/j.apsusc.2018.11.213
  • Dergi Adı: APPLIED SURFACE SCIENCE
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1093-1100
  • İstanbul Kültür Üniversitesi Adresli: Evet

Özet

In this work, we demonstrate an alteration of mechanical, electrophysical, piezo- and ferroelectric properties of polyvinylidene fluoride/trifluoroethylene P(VDF-TrFE) copolymer at the composition of 70/30 mol% in the presence of lithium niobate (LiNbO3) fillers. The micro- and nanoscale measurements of the elastic modulus suggest a two-fold increase in the mechanical rigidity of the P(VDF-TrFE) film after embedding the LiNbO3. The enhancement of local piezo- and ferroelectric properties of the modified polymer is evidenced by the increase of the direct piezoelectric coefficient from 27.1 pm/V to 36.1 pm/V. This increase is supposed to be associated with a significant contribution from Li-ion diffusion (the surface nanoelectrochemistry effect). This suggestion is supported by the observation of irreversible dc bias voltage-induced Li-ion extraction contributing to the locally-measured piezoresponse. The dynamics of the Li-ion diffusion, studied by electrochemical strain time spectroscopy, shows a decrease of the diffusion coefficient for an area poled by dc bias voltage as compared with a pristine one. This decrease confirms the existence of irreversible electrochemical processes during the local piezoelectric measurements. At the same time, X-ray diffraction and micro-Raman data suggest the integrity of the intramolecular structure of the P(VDF-TrFE) copolymer after embedding the LiNbO3 fillers. This is a key achievement allowing to keep the structure-related parameters specific to the pure P(VDF-TrFE) copolymer. The obtained results reveal a crucial role of the fillers in attaining the desired functional behavior, thus paving the way towards the development of advanced sensors, transducers, actuators, and piezoelectric devices.