Premium
Polymorphism of a semi‐crystalline diketopyrrolopyrrole‐terthiophene polymer
Author(s) -
Li Mengmeng,
Leenaers Pieter J.,
Li Junyu,
Wienk Martijn M.,
Janssen René A. J.
Publication year - 2021
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20200673
Subject(s) - terthiophene , polymorphism (computer science) , polymer , materials science , polymer science , polymer chemistry , chemistry , composite material , biochemistry , genotype , gene
Few semiconducting polymers are known that possess more than one semi‐crystalline structure. Guidelines for rationalizing or creating polymorphism in these materials do not exist. Two different semi‐crystalline polymorphs, β 1 and β 2 , and an amorphous α phase have recently been identified for alternating diketopyrrolopyrrole‐quaterthiophene copolymers (PDPP4T). The polymorphs differ structurally by the π–π stacking distance, and electronically by the optical bandgap and charge carrier mobility. Here we investigate the corresponding terthiophene (PDPP3T) derivatives, to study the effect of the relative orientation of adjacent DPP units on the polymorphism. In PDPP3T, the relative orientation of DPP units alternates along the chain, while in PDPP4T it is constant. We show that the two polymorphs, β 1 and β 2 , can also be generated for a PDPP3T polymer in solution and thin film. Interestingly, compared to PDPP4T, more solvents can induce the two distinct semi‐crystalline polymorphs for PDPP3T via a β 1 → α → β 2 polymorphic transition.