A New Design Strategy
for the Synthesis of Unsubstituted
Polythiophene with Defined High Molecular Weight
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Abstract
Unsubstituted polythiophene (PT) with defined and known
high molecular
mass (up to ca. 36 000 g mol<sup>–1</sup> (<i>M</i><sub>w</sub>)) and low structural defects (ca. 3.6 mol %) as highly
attractive semiconducting material is presented. The new synthetic
strategy for this polymer is based on the combination of Stille-type
polycondensation reactions, ultrasound-assisted dispersion technique,
and microwave-assisted ring-closure reactions. The use of Stille-type
polycondensation produces a diketal prepolymer with good solubility
and prescient and controllable degree of polymerization (DP) for the
final insoluble PT. Ultrasonication preserves a high interfacial area,
while microwave provides fast and effective heating for the last heterophase
ring-closure reaction. The characterization of the final product by
solid-state NMR, TEM, UV–vis absorption and fluorescence emission
spectroscopy, XRD, TGA, and
conductivity measurements exhibits significant features for electronic
and photoelectronic applications, such as broadened absorption, relatively
high crystallinity, high thermal stability, and typical semiconducting
properties