Mechanical, Thermal, and Electrical Properties of Flexible Polythiophene with Disiloxane Side Chains

Abstract

Poly(3‐hexylthiophene) (P3HT) is widely shown to have considerable advantages in photovoltaic cells, including excellent electrical performance, but its fragility remains a challenge for material applications and processing of stretchable devices. Herein, high‐molecular‐weight and highly regioregular poly(3‐substituted thiophene) with disiloxane moieties in the side chains (P3SiT) is synthesized. An investigation of the molecular structure and physical properties of self‐supported cast films of P3SiT reveals excellent flexible mechanical properties derived from the disiloxane groups in the side chains. The larger fracture strain reaches over 200% compared with that of poly(3‐hexylthiophene) (14%). In addition, its Young's modulus (43 MPa) and low glass transition temperature (−10 °C) result in a typical elastic mechanical property. For the electrical property, the sheet resistivity of the drawn thiophene polymer shows the value almost equal to that of poly(3‐hexylthiophene). The anisotropy of electrical resistivity is observed due to orientation of the drawn polymer.

Formal preparation of regioregular and alternating thiophene–thiophene copolymers bearing different substituents

“…Two remarkable peaks were observed at 2θ = 3.94° and 12.18°, respectively, as shown in Figure 2a. The result suggested that the thin film of the alternating copolymer 6c had a bilayer lamellar structure with 7.3 Å and 22.4 Å distances, respectively (Figure 2b) [13,29,30]. Molecular modeling of the alternating copolymer 6c suggested chain lengths of 11.6 Å and 2.2 Å, respectively.…”

Synthesis of block copolymers comprised of poly(3‐hexylthiophene) segment with trisiloxane side chains and their application to organic thin film transistor

“…Mori and coworkers reported the synthesis of regioregular polythiophene derivatives having soft siloxane units in the side chains . Indeed, the films of siloxane‐containing polythiophenes showed 2 orders of magnitude smaller Young's modulus and 20 times higher elongation at break than P3HT.…”

“…Mori and coworkers reported the synthesis of regioregular polythiophene derivatives having soft siloxane units in the side chains. [21][22][23] Indeed, the films of siloxane-containing polythiophenes showed 2 orders of magnitude smaller Young's modulus and 20 times higher elongation at break than P3HT. Previously, we also synthesized a regioregular polythiophene derivative with a trisiloxane group in the side chains via a hexamethylene spacer (P3SiHT) as shown in Figure 1.…”

A formal preparation of regioregular and alternating thiophene−thiophene copolymers bearing different substituents

“…Two remarkable peaks were observed in 2θ = 3.94° and 12.18°, respectively, as shown in Fig 2 (a). The result suggests that the thin film of the alternating copolymer 6c shows bilayer lamellar structure involving 7.3 Å and 22.4 Å distances, respectively, 13,29,30 (Fig 2(b)) The molecular modeling of the alternating copolymer 6c suggests the chain lengths of 11.6 Å and 2.2 Å, respectively. The values of the observed layer distances of copolymer 6c closely corresponds to the twice values 11.6 x 2 and 2.2 x 2 (Fig 2(c) In summary, we have shown that formal alternating thiophene−thiophene copolymers were synthesized when a differently-substituted halobithiophene was employed as a monomer by nickel-catalyzed deprotonative polymerization was applied.…”