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Well-Defined Block Copolymers with Triphenylamine and Isocyanate Moieties Synthesized via Living Anionic Polymerization for Polymer-Based Resistive Memory Applications: Effect of Morphological Structures on Nonvolatile Memory Performances
journal contribution
posted on 2014-12-23, 00:00 authored by Beom-Goo Kang, Jingon Jang, Younggul Song, Myung-Jin Kim, Takhee Lee, Jae-Suk LeeThe
anionic block copolymerization of 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine
(A) with n-hexyl isocyanate (B) was performed using potassium naphthalenide (K-Naph) in THF at
−78 and −98 °C in the presence of sodium tetraphenylborate
(NaBPh4) to afford the well-defined block copolymers for
investigating the effect of morphological structures on electrical
memory performances. The well-defined functional block copolymers
(PBAB) with different block ratios had predictable molecular
weights (Mn = 17 700–79 100
g/mol) and narrow molecular weight distributions (Mw/Mn = 1.14–1.19).
It was observed from transmission electron microscopy (TEM) that the
block copolymers showed different morphological structures depending
on block ratios. Although all memory devices fabricated from the resulting
block copolymers with different block compositions equally exhibited
nonvolatile resistive switching characteristics, which are governed
by the trap-controlled space-charge-limited current (SCLC) conduction
mechanism and filament formation, it was found that electrical memory
performances of each device varied depending on morphological structures
of the block copolymer films.