SYNTHESIS OF CONJUGATED POLYMERS VIA RANDOM COPOLYMERIZATION TO INVESTIGATE THERMAL PROPERTIES

Open Access
- Author:
- Gill, Michael
- Area of Honors:
- Chemical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dr. Enrique Daniel Gomez, Thesis Supervisor
Scott Thomas Milner, Thesis Honors Advisor - Keywords:
- conjugated polymers
organic-photovoltaics
PPTBT
PPT6BT
PFTBT
PFT6BT
copolymers
crystallinity
liquid-crystalline
differential scanning calorimetry
synthesis
Suzuki polycondensation - Abstract:
- The utility of conjugated polymers stems from their wide uses in organic photovoltaics, organic field-effect transistors, and organic light-emitting diodes. One of the advantages of conjugated polymers over traditional silicon-based electronics is their chemical tunability. Conjugated polymers can be customized to have desirable properties based on their intended application. These polymers have been studied to understand how changes to their structure affect electronic properties, including analysis of their glass transition and melting transition; however, these models have not been extensively studied. In this study, two polymers, Poly-((2,5- dihexylphenylene)-1,4-diyl-alt-[4,7-bis(thiophen-5-yl)-2,1,3-benzothiadiazole]-2’,2"-diyl) (PPTBT) and Poly-((9,9-bis(2-octyl)-fluorene-2,7-diyl)-alt-(4,7-di(thiophene-2-yl)-2,1,3-benzothiadiazole)-5′,5″-diyl) (PFTBT) were synthesized with varying concentrations of 4,7-bis(5-bromo-4-hexylthiophen-2-yl)-2,1,3-benzothiadiazole (T6BT). This was done to analyze how the random addition of T6BT affects the physical macroscopic properties of the polymers including crystallinity and the phase transition temperatures. Addition of T6BT was expected to improve the solubility of the polymer during processing with minimal impact on thermal properties. Thermal analysis was conducted using Differential Scanning Calorimetry. Poly-((2,5-dihexylphenylene)-1,4-diyl-alt-[4,7-bis(3-hexylthiophen-5-yl)-2,1,3-benzothiadiazole]-2′,2′′-diyl) or PPT6BT demonstrated a liquid crystallinity with a nematic to isotropic transition at 146C while no other polymers demonstrated substantial crystallinity or liquid crystalline properties.