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Characteristics and Nomenclature of Copolymers

Characteristics and Nomenclature of Copolymers

Copolymers are the products obtained from the polymerization of multiple monomer species. So, in a polymer chain itself, there can be multiple repeating units that come from different monomers. The process of synthesizing a polymer from different monomer species is called copolymerization. When two monomers are involved, the polymer is known as a bipolymer. Polymers with three and four monomers are termed terpolymers and quaterpolymers, respectively. Figure 1 depicts the copolymerization of...

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Fabrication and Characterization of Disordered Polymer Optical Fibers for Transverse Anderson Localization of Light

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Published on: July 29, 2013

Optical absorption in donor-acceptor polymers--alternating vs. random.

Andreas Karolewski¹, Anne Neubig, Mukundan Thelakkat

¹Theoretical Physics IV, University of Bayreuth, 95440 Bayreuth, Germany. stephan.kuemmel@uni-bayreuth.de.

Physical Chemistry Chemical Physics : PCCP

|October 25, 2013

Summary

The arrangement of donor and acceptor units in extended molecules has a limited effect on optical absorption. Other factors beyond the single molecule level significantly influence the observed optical gap in polymers.

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Fabrication and Characterization of Disordered Polymer Optical Fibers for Transverse Anderson Localization of Light

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Area of Science:

Materials Science
Theoretical Chemistry
Organic Electronics

Background:

Understanding the optical absorption of extended molecules is crucial for developing new materials, especially low band gap polymers.
The arrangement of donor and acceptor units significantly impacts molecular properties, but its precise influence on optical absorption requires further investigation.

Purpose of the Study:

To investigate the influence of donor-acceptor unit arrangement (alternating vs. random) on the optical absorption of extended molecules.
To determine the energetic position of the first electronic transition in thiophene-benzothiadiazole oligomers.
To compare theoretical predictions with experimental data for synthesized systems.

Main Methods:

Time-dependent density functional theory (TD-DFT) using non-empirically tuned range-separated hybrid functionals for theoretical calculations.
Synthesis of extended oligomers comprising thiophene (donor) and 2,1,3-benzothiadiazole (acceptor) units.
Critical comparison of theoretical and experimental optical absorption data.

Main Results:

The specific arrangement of donor and acceptor monomers has a limited impact on the optical gap of the studied molecules.
Theoretical calculations accurately predicted electronic excitations.
Experimental optical gaps were found to be limited by effects beyond the single-molecule level.

Conclusions:

The arrangement of donor and acceptor units has a minor influence on the optical gap compared to other factors.
Intermolecular effects play a significant role in determining the experimentally observed optical gap in these systems.
This study provides insights into the design principles for organic electronic materials.