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Conductivity of oriented bis-azo polymer films
Dirk Apitz1, Ralph Peter Bertram, Nils Benter
1Optics and Plasma Research Department, Risø National Laboratory, 4000 Roskilde (Denmark). dirk.apitz@risoe.dk
Summary
Investigating conductivity in bis-azo chromophore polymer films reveals that chromophore orientation impacts charge mobility. Microcrystallization significantly boosts conductivity by enabling hole hopping over ionic conduction.
Area of Science:
- Materials Science
- Polymer Chemistry
- Conductivity Physics
Background:
- Bis-azo chromophore polymer films exhibit electro-optic and photoaddressable properties.
- Understanding charge transport mechanisms is crucial for advanced material applications.
Purpose of the Study:
- To investigate the conductivity properties of bis-azo chromophore polymer films.
- To determine the influence of chromophore orientation and thermal transitions on charge carrier mobility and conductivity.
Main Methods:
- Corona poling of polymer films at various temperatures.
- Dielectric spectroscopy to measure frequency-dependent conductivity.
- Thermal analysis to observe transitions above the glass transition temperature.
Main Results:
- Chromophore orientation significantly alters charge-carrier mobility.
- Ionic conductivity predominates in disordered states.
- Hole hopping becomes dominant upon transition to a liquid-crystalline phase at elevated temperatures.
- Microcrystallization induced by heating enhances overall conductivity.
Conclusions:
- The charge transport mechanism in these polymers is tunable via thermal treatment and chromophore alignment.
- Microcrystallization is a key factor in enhancing conductivity in bis-azo chromophore polymers.