Oligo(ethylene glycol) as side chains of conjugated polymers for optoelectronic applications

Solution processable conjugated polymers are always composed of a rigid polymer backbone and flexible side chains. The typical side chains of conjugated polymers are alkyl chains, which are hydrophobic. Oligo(ethylene glycol) (OEG) chains, which are hydrophilic, have also been widely used as side chains of conjugated polymers. Compared with alkyl chains, OEG chains possess some characteristics, such as hydrophilicity, high polarity, high flexibility and ionic conductivity. As a result, OEG chains greatly affect the opto-electronic properties, molecular stacking behaviors in thin films, and opto-electronic device performance of the resulting conjugated polymers. Conjugated polymers bearing OEG side chains can not only show improved opto-electronic device performance, but also enable new opto-electronic device applications. In this review, using several typical examples, we summarize conjugated polymers bearing OEG side chains for optoelectronic applications.