Phase transition behaviors of the self-assembled structures of a dihydrazide derivative

ABSTRACT

Precipitates or xerogels of 1,3-bis[(3,4-dioctyloxy phenyl) hydrazide] phenylene (BP8-C) from ethanol or toluene were demonstrated to show three different aggregate structures depending on different cooling procedure, i.e. cubic phase and two kinds of hexagonal columnar phase (denoted as Col_h1 and Col_h2). DSC measurement indicated that cubic-Col_h1 and Col_h1-Col_h2 transition showed endothermic behavior while Col_h2-Col_h1 transition showed exothermic, indicating cubic structure was the most stable. Annealing of the BP8-C/ethanol suspension or the BP8-C/toluene gel caused the gradual structural transitions from either Col_h1 to cubic or Col_h2 to cubic phase. Higher incubation temperature, longer annealing time, or polar solvent could accelerate the transitions from instability structure to stability ones in the gels.

KEYWORDS:

• Dihydrazide derivative
• self-assembly
• phase transition

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Funding

The authors are grateful to the National Science Foundation Committee of China (Project no. 51073071, 21072076 and 51103057) and Project 985-Automotive Engineering of Jilin University for financial support of this work; Project 985-Automotive Engineering of Jilin University.