ao8b02095_si_001.pdf (1.22 MB)
Digital Memory Characteristics of Aromatic Polyimides Based on Pyridine and Its Derivatives
journal contribution
posted on 2018-10-11, 11:33 authored by Yongjin Kim, Sungjin Song, Der-Jang Liaw, Ying-Chi Huang, Yong-Gi Ko, Kyuwook Ihm, Jehan Kim, Moonhor ReeSoluble aromatic polyimides and polyvinyls
were prepared by incorporating
pyridine moiety and its derivatives in the backbone and the side groups,
respectively: 6F-Py-i polymers based on the polyimide
backbone (6F-Py-1 to 6F-Py-7) and PVPy-i polymers
based on the polyvinyl backbone (PVPy-1 to PVPy-4). All polymers were
found to be amorphous. The 6F-Py-i polymers were
thermally stable up to 511–545 °C; the PVPy-i polymers were stable up to 362–376 °C. Their glass transitions,
thin film densities, molecular orbitals, and band gaps were determined.
The electrical devices fabricated with the polymers in an electrode/polymer/electrode
structure revealed p-type unipolar write-once-read-many times (namely,
permanent) or dynamic random access memory or dielectric behavior,
depending on the substituents of the pyridine unit and the film thicknesses.
In particular, such digital memory characteristics were found to originate
from the pyridine moieties possessing a high charge affinity in the
polymers. However, the pyridine moieties were found to still need
at least two or more aromatic substituents to get enough power to
stabilize charges via utilizing the resonance effects provided by
the substituents. Overall, this study demonstrated that the pyridine
unit conjugated with two or more aromatic substituents is a very useful
component to design and synthesize digital memory materials based
on thermally stable polyimides and other high performance polymers.
The 6F-Py-i polymers have potential for the low-cost
mass production of high-performance programmable unipolar permanent
memory devices with very low power consumption.