Self-Assembly of Carbohydrate-block-Poly(3-hexylthiophene) Diblock Copolymers into Sub-10 nm Scale Lamellar Structures

Abstract

We here report the synthesis of a new class of carbohydrate-based block copolymers, poly(3-hexylthiophene)-block-peracetylated maltoheptaose (P3HT-b-AcMal7) and poly(3-hexylthiophene)-block-maltoheptaose (P3HT-b-Mal7), and their bulk and self-assembled thin films morphological characterizations by atomic force microscopy, transmission electron microscopy, and small-angle X-ray scattering. The block copolymers were synthesized via copper(I)-catalyzed 1,3-dipolar azide–alkyne cycloaddition of azido-functionalized AcMal7 and end-functionalized P3HT with alkyne group prepared by modified Grignard metathesis polymerization, followed by deacetylation of the AcMal7 block. The half-pitch of sub-10 nm scale lamellar structures, one of the smallest domain sizes of microphase separated block copolymers reported to date, was self-organized in the bulk and thin films of P3HT-b-AcMal7 by thermal annealing above the melting temperature of the P3HT segment. Meanwhile, thermodynamic microphase separation of P3HT-b-Mal7 wa...