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Abstract: We report on the development of the solid-state structure from the melt of crystalline–crystalline diblock copolymers consisting of the semiconducting poly(3-hexylthiophene) (P3HT) and insulating polyethylene (PE) – a material combination that previously was shown to feature promising characteristics for applications in flexible organic electronics. The nature of the structures obtained from the melt was found to generally be dictated by crystallization of the PE block, which solidified after the P3HT sequence. This resulted in the formation of classical spherulitic structures for diblock copolymers of low P3HT content. At P3HT contents exceeding 10–20wt%, the semiconductor block increasingly hampered crystallization of the PE moiety, with the P3HT entity arranging into columnar and at higher content into lamellar micelle-type domains. Unlike the rate of crystal growth of the two moieties, interestingly, the dimensionality of both entities of the diblock copolymers was found to be unaffected by the presence of the dissimilar block. [Copyright &y& Elsevier]

This article focuses on a study crystalline block copolymers of regioregular poly (3-hexylthiophene) and polyethylene by ring-opening metathesis polymerization. The established route to semiconducting block copolymers typically combines a crystalline or amorphous conjugated polymer block with an amorphous, random-coil polymer that provides solubility and facilitates processing. At temperatures less than 70 degrees C, the copolymers are resistant to solvents, such as THF and chloroform; however, they dissolve at more elevated temperatures in, for instance, xylenes and chlorobenzenes.

Blends and other multicomponent systems are used in various polymer applications to meet multiple requirements that cannot be fulfilled by a single material. In polymer optoelectronic devices it is often desirable to combine the semiconducting properties of the conjugated species with the excellent mechanical properties of certain commodity polymers. Here we investigate bicomponent blends comprising semicrystalline regioregular poly(3-hexylthiophene) and selected semicrystalline commodity polymers, and show that, owing to a highly favourable, crystallization-induced phase segregation of the two components, during which the semiconductor is predominantly expelled to the surfaces of cast films, we can obtain vertically stratified structures in a one-step process. Incorporating these as active layers in polymer field-effect transistors, we find that the concentration of the semiconductor can be reduced to values as low as 3 wt% without any degradation in device performance. This is in stark contrast to blends containing an amorphous insulating polymer, for which significant reduction in electrical performance was reported. Crystalline–crystalline/semiconducting–insulating multicomponent systems offer expanded flexibility for realizing high-performance semiconducting architectures at drastically reduced materials cost with improved mechanical properties and environmental stability, without the need to design all performance requirements into the active semiconducting polymer itself. [ABSTRACT FROM AUTHOR]