TY - JOUR
T1 - Self-assembly and digital memory characteristics of an oxadiazole-containing brush polymer in nanoscale thin films
AU - Kwon, Wonsang
AU - Ahn, Byungcheol
AU - Kim, Yongjin
AU - Kim, Young Yong
AU - Ree, Brian J.
AU - Ko, Yong Gi
AU - Lee, Jinseok
AU - Ree, Moonhor
N1 - Publisher Copyright:
© 2014 by American Scientific Publishers.
PY - 2014
Y1 - 2014
N2 - The self-assembly characteristics in nanoscale thin films and digital memory behaviors of poly(5-phenyl-1,3,4-oxadiazol-2-yl-[1,1'-biphenyl]carboxyloxy-n-nonyl acrylate), a well-defined brush polymer bearing oxadiazole moieties, were investigated. The synchrotron grazing incidence X-ray scattering analysis found that the brush polymer molecules in thin films always formed a multibilayer structure consisting of fully extended backbone and bristle conformations. In the structure, the bristles were interdigitated in part; In particular, the oxadiazole containing mesogens were fully interdigitated via the π-π interaction of the biphenyl linkers. The multibilayer structured film undergoes three phase transitions (glass, melting, and liquid crystal-to-isotropic transitions) below the degradation temperature of 350 °C. The film's overall crystallinity, as well as the orientation of the multibilayer structure was found to depend on the film formation process conditions. While the as-cast films had a relatively low crystallinity and formed a vertical multibilayer structure with a broad orientation distribution, the thermally annealed films had a high crystallinity and formed an almost perfect horizontally oriented multibilayer structure. These different morphologies led different digital memory modes in devices; the as-cast films revealed volatile memory behavior, whereas the thermally annealed films showed permanent memory characteristics. These memory modes originated from the oxadiazole moieties in the two different film morphologies. The memory modes were demonstrated for the polymer films in the thickness range 5-50 nm.
AB - The self-assembly characteristics in nanoscale thin films and digital memory behaviors of poly(5-phenyl-1,3,4-oxadiazol-2-yl-[1,1'-biphenyl]carboxyloxy-n-nonyl acrylate), a well-defined brush polymer bearing oxadiazole moieties, were investigated. The synchrotron grazing incidence X-ray scattering analysis found that the brush polymer molecules in thin films always formed a multibilayer structure consisting of fully extended backbone and bristle conformations. In the structure, the bristles were interdigitated in part; In particular, the oxadiazole containing mesogens were fully interdigitated via the π-π interaction of the biphenyl linkers. The multibilayer structured film undergoes three phase transitions (glass, melting, and liquid crystal-to-isotropic transitions) below the degradation temperature of 350 °C. The film's overall crystallinity, as well as the orientation of the multibilayer structure was found to depend on the film formation process conditions. While the as-cast films had a relatively low crystallinity and formed a vertical multibilayer structure with a broad orientation distribution, the thermally annealed films had a high crystallinity and formed an almost perfect horizontally oriented multibilayer structure. These different morphologies led different digital memory modes in devices; the as-cast films revealed volatile memory behavior, whereas the thermally annealed films showed permanent memory characteristics. These memory modes originated from the oxadiazole moieties in the two different film morphologies. The memory modes were demonstrated for the polymer films in the thickness range 5-50 nm.
KW - Digital memory behaviors
KW - Grazing incidence X-ray scattering
KW - Multibilayer structure
KW - Oxadiazole-containing brush polymer
KW - Self-assembly
UR - http://www.scopus.com/inward/record.url?scp=84920286053&partnerID=8YFLogxK
U2 - 10.1166/sam.2014.2230
DO - 10.1166/sam.2014.2230
M3 - Article
AN - SCOPUS:84920286053
SN - 1947-2935
VL - 6
SP - 2289
EP - 2297
JO - Science of Advanced Materials
JF - Science of Advanced Materials
IS - 11
ER -