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Intermolecular Interaction-Induced Hierarchical Transformation in 1D Nanohybrids: Analysis of Conformational Changes by 2D Correlation Spectroscopy
journal contribution
posted on 2008-01-23, 00:00 authored by Ho Seok Park, Yeong Suk Choi, Young Mee Jung, Won Hi HongWe have examined both self-assembly and confinement effect in room-temperature ionic liquid
(RTIL)-aluminum hydroxide hybrids (RAHs) to attain a fundamental understanding of special phenomena
in nanoscale spaces as well as to design functional nanomaterials for practical applications. Phase-controlled
one-dimensional (1D) RAHs were synthesized through a simple ionothermal process. The RAHs were
hierarchically transformed in terms of the molecular structures, morphologies, and phases of the materials
during the ionothermal process with respect to the concentration of RTIL. In addition to the hierarchical
transformation, the RTIL/aluminum hydroxide nanohybrids revealed unexpected physical behaviors, including
thermal transition variation of the RTIL in confined environments and a phase transition from nanosolid to
nanoliquid affected by changes of the melting points. More importantly, intermolecular interaction induced-self-assembly and confinement effect of RTILs inside an integrated hybrid system, which have not been
clearly explained to date, were analyzed by 2D infrared correlation spectroscopy (2D IR COS); dynamic
behaviors of RTILs, i.e., sequentially spatial reorientation and kinetically conformational changes, were
attributed to the interactions between RTILs and aluminum hydroxides. 2D IR COS offers a new way to
interpret highly complex, veiled systems such as the formation mechanism of nanoparticles, biomineralization, self/supramolecular assembly, and nanoconfinement.