Self-assembly of amphiphilic conjugated diblock copolymers into one-dimensional nanoribbons

The colloidal self-assembly of a new conjugated diblock copolymer of a polythiophene derivative, poly[3-(2,5,8,11-tetraoxatridecanyl)thiophene]-block- poly(ethylene glycol) (PTOTT-b-PEG), led to various well-defined assembly structures such as vesicles, sheets, and nanoribbons. A unique and technologically relevant nanoribbon structure with a dimension reaching tens of micrometers was formed in water when polar protic solvents were used as initial cosolvents. Self-assembly of PTOTT-b-PEG in various solvent compositions and polymer concentrations indicated that the hydrogen bonding between the diblock copolymer and the self-assembly medium plays an important role in determining the self-assembly structure and that the final assembly structure should be the result of a delicate interplay between hydrogen bonding and π-π interactions. This study demonstrates that the addition of hydrogen bonding capability and amphiphilicity in the self-assembly of conjugated polymers can lead to many interesting well-defined assembly structures that are not typically found in conjugated polymers.