The ferroelectric copolymer of vinylidene fluoride and trifluoroethylene [P(VDF-TrFE)] has been developed for an broad range of applications including sensing, actuation, data storage, energy harvesting, etc. And the continuous demand for miniaturization requires fabricating nanostructured materials. While materials at the nanometer scale always exhibit properties strikingly different from those of the bulk, the performance of P(VDF-TrFE) is closely related to their nanocrystal structure. Understanding the details of their growth process and microscopic performance change is of great importance.
By using a special in situ hot stage Piezoresponse Force Microscopy (PFM) technique,Professor GUO Dong’s team at the Institute of Acoustics, Chinese Academy of Sciences (IACAS) systemically investigated the growth process of nanocrystals in spin-coated P(VDF-TrFE) films and their simultaneous piezoelectric response evolution. Professor GUO’s team found that the individual grains in the P(VDF-TrFE) film had a uniform molecular orientation, while different nanocrystals might show different molecular orientation. Surprisingly, the nanocrystals still showed a strong piezoelectric response even close to its meting temperature, revealing a diffused ferroelectric phase transition nature that is related to the coexistence of crystalline and amorphous phases in the copolymer.
The work titled “In situ observation of the nanocrystal growth and their piezoelectric performance change in P(VDF-TrFE) films by hot stage piezoresponse force microscopy” has been published online: http://jap.aip.org/resource/1/japiau/v113/i18/p187210_s1 and on J. Appl. Phys. (Vol.113, Issue 18, 187210, 2013). The research result is highlighted on the cover of the journal.
Fig. 1 Cover image of J. Appl. Phys.113 18 187210 (2013). The three colorful PFM amplitude images in the center illustrate the evolution of piezoelectric response of individual grains with increasing temperature (Image by GUO).
Contact:
GUO Dong
Institute of Acoustics, Chinese Academy of Sciences
E-mail: dong.guo@mail.ioa.ac.cn