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High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
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Extensively Reversible Thermal Transformations of a Bistable, Fluorescence-Switchable Molecular Solid: Entry into
P Srujana1, T P Radhakrishnan2
1School of Chemistry, University of Hyderabad, Hyderabad-500 046 (India) http://chemistry.uohyd.ac.in/∼tpr/
Angewandte Chemie (International Ed. in English)
|May 6, 2015
Summary
Novel molecular materials exhibit reversible switching between crystalline and amorphous states, enabling potential applications beyond thermal storage. These functional phase-change materials (PCMs) also show tunable fluorescence properties.
Area of Science:
- Materials Science
- Supramolecular Chemistry
- Organic Electronics
Background:
- Functional phase-change materials (PCMs) are predominantly inorganic, limiting molecular material applications.
- Existing organic PCMs are mainly for thermal storage, unlike inorganic counterparts used in data storage.
- Reversible amorphous-crystalline transitions in molecular solids necessitate a balance between structural stability and flexibility.
Purpose of the Study:
- To develop novel molecular materials exhibiting reversible amorphous-crystalline transformations.
- To explore the potential of these materials in advanced applications beyond thermal energy storage.
- To investigate the relationship between molecular structure and phase-change behavior, including optical properties.
Main Methods:
- Synthesis of novel diaminodicyanoquinodimethane derivatives.
- Characterization of their supramolecular assembly, including interlinked helical structures.
- Investigation of conformational flexibility using alkoxyalkyl chains.
- Analysis of reversible thermal transformations between crystalline and amorphous states.
- Evaluation of fluorescence emission switching upon phase transition.
Main Results:
- Successfully synthesized diaminodicyanoquinodimethanes with interlinked helical assemblies and flexible chains.
- Demonstrated highly reversible thermal transformations between bistable crystalline and amorphous forms.
- Observed significant switching in fluorescence emission energy and intensity correlated with the phase changes.
- Established a molecular design principle for functional molecular phase-change materials.
Conclusions:
- Novel molecular materials based on diaminodicyanoquinodimethanes exhibit reversible phase-change properties.
- These materials offer potential for advanced applications in areas like information storage and responsive optical devices.
- The design integrating supramolecular assembly and flexible chains is crucial for achieving functional molecular phase-change behavior.
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