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Mesogene-polymer backbone coupling in side-chain polymer liquid crystals, studied by high magnetic-field-induced
M I Boamfa1, K Viertler, A Wewerka
1Research Institute for Materials, High Field Magnet Laboratory, University of Nijmegen, Toernoiveld 1, 6525 ED, The Netherlands. boamfa@sci.kun.nl
Physical Review Letters
|February 7, 2003
Summary
Cooling liquid crystals in a magnetic field creates ordered, transparent, and birefringent materials. This alignment is stable and depends on mesogene-polymer interactions.
Area of Science:
- Materials Science
- Polymer Science
- Condensed Matter Physics
Background:
- Liquid crystals exhibit unique optical and electrical properties.
- Side-chain liquid crystal polymers (SCLCPs) offer tunable characteristics.
- Controlling molecular order in polymers is crucial for advanced materials.
Purpose of the Study:
- To investigate the effect of magnetic field-induced cooling on SCLCPs.
- To determine the stability and properties of aligned SCLCPs.
- To understand the role of mesogene-polymer backbone coupling in alignment.
Main Methods:
- Cooling SCLCPs from isotropic to nematic and glass phases under a magnetic field.
- Characterization of optical properties (transparency, birefringence) and macroscopic order.
- Investigating alignment stability after field removal and temperature-dependent de-alignment.
Main Results:
- Achieved macroscopically ordered, transparent, and strongly birefringent SCLCPs.
- Alignment was retained after magnetic field removal.
- A threshold magnetic field (B(th)) was necessary for alignment, dependent on chemical structure.
- B(th) correlates with mesogene-polymer backbone coupling strength.
Conclusions:
- Magnetic field-induced cooling is an effective method for aligning SCLCPs.
- The mesogene-polymer backbone interaction dictates the stability of the induced alignment.
- Aligned SCLCPs possess stable, desirable properties for potential applications.
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