Polythiophenes
“Polythiophenes(PTs) result from the polymerization of thiophenes, a sulfur heterocycle, that can become conducting when electrons are added or removed from the conjugated π-orbitals via doping.”
“The study of polythiophenes has intensified over the last three decades. The maturation of the field of conducting polymers was confirmed by the awarding of the 2000 Nobel Prize in Chemistry to Alan Heeger, Alan MacDiarmid, and Hideki Shirakawa “for the discovery and development of conductive polymers." The most notable property of these materials, electrical conductivity, results from the delocalization of electrons along the polymer backbone – hence the term “synthetic metals”. However, conductivity is not the only interesting property resulting from electron delocalization. The optical properties of these materials respond to environmental stimuli, with dramatic color shifts in response to changes in solvent, temperature, applied potential, and binding to other molecules. Both color changes and conductivity changes are induced by the same mechanism—twisting of the polymer backbone, disrupting conjugation—making conjugated polymers attractive as sensors that can provide a range of optical and electronic responses.”
(Wikipedia, Polythiophenes, 7/28.2011)
Polymers /Resins
Polythiophene Copolymers
Polythiophene Nanoparticles
Polythiophene Photovoltaics
Recent Journal Articles
A polythiophene derivative bearing TEMPO as a cathode material for rechargeable batteries
(2283-2294) European Polymer Journal 47 #12 (2011)
Aydın et al, Turkey and North Dakota, synthesized a polythiophene derivative bearing TEMPO radical by oxidative chemical polymerization of its monomer. We demonstrated, for the first time, construction and charge/discharge characteristics of an organic radical battery utilizing a TEMPO bearing polythiophene based cathode material. The battery had an initial specific discharge capacity of 79 A h/kg (87% of the theoretical capacity) and an average output voltage of 3.6 V. The specific energy capacity initially discharged was 268 W h/kg. (RDC 11/16/2011)
Effect of Regioregularity on the Semicrystalline Structure of Poly(3-hexylthiophene)
(7088–7091) Macromolecules 44 #18 (2011)
Anisotropic Structure and Charge Transport in Highly Strain-Aligned Regioregular Poly(3-hexylthiophene)
(3697–3705) Advanced Functional Materials 21 #19 (2011)
O'Connor et al pf the National Institute of Standards and Technology, Maryland and Stanford Synchrotron Radiation Lightsource, California, developed a method of strain-aligning polymer films and applied to regioregular poly(3-hexylthiophene) (P3HT), showing several important features of charge transport. The polymer backbone is shown to align in the direction of applied strain resulting in a large charge-mobility anisotropy, where the in-plane mobility increases in the applied strain direction and decreases in the perpendicular direction. In the aligned film, the hole mobility is successfully represented by a two-dimensional tensor, suggesting that charge transport parallel to the polymer backbone within a P3HT crystal is strongly favored over the other crystallographic directions. Hole mobility parallel to the backbone is shown to be high for a mixture of plane-on and edge-on packing configurations, as the strain alignment is found to induce a significant face-on orientation of the originally highly edge-on oriented crystalline regions of the film. This alignment approach can achieve an optical dichroic ratio of 4.8 and a charge-mobility anisotropy of 9, providing a simple and effective method to investigate charge-transport mechanisms in polymer semiconductors. (RDC 9/26/2011)
Regioselective grignard metathesis reaction of 2,5-dibromo-3-(6′-hexylpyridine-2′-yl)thiophene and kumada coupling polymerization
(4013–4020)Journal of Polymer Science Part A: Polymer Chemistry 49 #18 (2011)
Takagi et al of Nagoya Institute of Technology, Japan, synthesized 2,5-Dibromo-3-(6′-hexylpyridine-2′-yl)thiophene (DBPyTh) by the Suzuki coupling reaction between two aromatic compounds followed by the bromination. The Grignard metathesis reaction of DBPyTh with isopropylmagnesium chloride proceeded in 85% conversion and the regioselective halogen–metal exchange at the 2-position was confirmed. Namely, 5-bromo-2-chloromagnesio-3-(6′-hexylpyridine-2′-yl)thiophene and 2-bromo-5-chloromagnesio-3-(6′-hexylpyridine-2′-yl)thiophene were generated in 90:10 molar ratio. Subsequently, the Kumada coupling polymerization was carried out using 1,3-bis(diphenylphosphinopropane)nickel(II) dichloride to obtain poly(3-(6′-hexylpyridine-2′-yl)thiophene) (PolyPyTh). (RDC 8/23/2011)
Review Articles
Structure and morphology control in thin films of regioregular poly(3-hexylthiophene)
( 1218–1233) Journal of Polymer Science B: Polymer Physics 49, #17 (2011)
Brinkmann of the University of Strasburg, France, reviewed the structural control in thin films of regioregular poly(3-hexylthiophene) (P3HT), a workhorse among conjugated semiconducting polymers. It highlights the correlation existing between processing conditions and the resulting structures formed in thin films and in solution. Particular emphasis is put on the control of nucleation, crystallinity and orientation. P3HT can generate a large palette of morphologies in thin films including crystalline nanofibrils, spherulites, interconnected semicrystalline morphologies and nanostructured fibers, depending on the elaboration method and on the macromolecular parameters of the polymer. Effective means developed in the recent literature to control orientation of crystalline domains in thin films, especially by using epitaxial crystallization and controlled nucleation conditions are emphasized. (RDC 7/27/2011)