Electronic Properties-Morphology Correlation of a Rod–Rod Semiconducting Liquid Crystalline Block Copolymer Containing Poly(3-hexylthiophene)

Abstract

The influence of the solvent and annealing temperature on the field-effect mobilities and morphologies of poly(3-hexylthiophene)-b-poly(γ-benzyl-l-glutamate) (P3HT-b-PBLG) rod–rod diblock copolymer has been investigated. Thin film X-ray diffraction studies show peaks originating from both P3HT and PBLG indicating that the crystalline nature of both the blocks is conserved after the formation of the block copolymer. It has been observed that the field-effect mobilities of the diblock copolymer are independent of the annealing temperatures for thin films deposited from both 1,2,4-trichlorobenzene and chloroform solvents. The correlation between the field-effect mobility and morphology indicates that the P3HT block self-assembles at the surface SiO2 dielectric.

Synthesis and characterization of side-chain thermotropic liquid crystalline copolymers containing regioregular poly(3-hexylthiophene)

“…The data were obtained from an untreated device and from the device treated with 8 Â 10 À3 M of octyltrichlorosilane. We previously reported the synthesis and electronic properties of liquid crystalline P3HT diblock copolymers containing poly(gbenzyl-L-glutamate) [43,44] (57 mol% of P3HT) and poly(hexyl isocyanate) (10 mol% of P3HT) [45]. These diblock copolymers displayed mobilities of 7 Â 10 À4 cm 2 V À1 s À1 and 1 Â 10 À3 cm 2 V À1 s À1 respectively, in OFET.…”

Poly(3-Hexylthiophene) Nanostructured Materials for Organic Electronics Applications

“…140 Bhatt and co-workers investigated rod-rod poly(3-hexylthiophene)-b-poly( -benzyl-L-glutamate) using thin film X-ray diffraction and noted signals in the profile corresponding to the individual blocks. 46 In particular, the lamellar spacing of P3HT was indicated by the 2 = 5 3 (16.7 Å) signal, and the characteristic hexagonal packing of PBLG was indicated by the 2 = 7 0 (12.6 Å) peak. The presence of both strong signals strongly indicates the semicrystalline packing from the copolymer's constituent blocks is retained.…”

“…11). 46 This polymer was synthesized by the combination of GRIM and ring opening polymerization of -benzyl-L-glutamate N -carboxyanhydride. 47 Using a different procedure, Bielawski's group also reported the synthesis of P3HT-b-PBLG.…”

“…43 44 The liquid crystalline diblock copolymer P34 displayed a different morphology as investigated by TMAFM. 46 The morphology of polymer thin film was dependent on solvent and annealing conditions. 46 The TMAFM analysis revealed the formation of nanoribbons for non-annealed films of diblock copolymer …”

“…114 Table I summarizes the field-effect mobility values measured for P3HT block copolymers. 46 54 71 78 The field-effect mobilities of P3HT block copolymers are one to three orders Table I. Field-effect mobilities of some P3HT block copolymers.…”