Polypeptide Composite Particle-Assisted Organization of π‑Conjugated Polymers into Highly Crystalline “Coffee Stains”

• Published in: ACS applied materials & interfaces Vol. 9; no. 39; pp. 34337 - 34348
• Main Authors: Rosu, Cornelia, Chu, Ping-Hsun, Tassone, Christopher J, Park, Katherine, Balding, Paul L, Park, Jung Ok, Srinivasarao, Mohan, Reichmanis, Elsa
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04.10.2017; American Chemical Society (ACS)
• Subjects: coffee ring effect; electronic materials; Marangoni flow; MATERIALS SCIENCE; OFET devices; polypeptide-assisted self-assembly; semiconducting polymers; OFET devices; coffee ring effect; electronic materials; Marangoni flow; polypeptide-assisted self-assembly; semiconducting polymers
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.7b10223

We demonstrate that homopolypeptides covalently tethered to anisotropically shaped silica particles induce crystalline ordering of representative semiconducting polymers. Films drop-cast from chloroform dispersions of poly­(γ-stearyl-l-glutamate) (PSLG) composite particles and poly­(3-hexythiophene) (P3HT) led to highly ordered crystalline structures of P3HT. Hydrophobic–hydrophobic interactions between the alkyl side chains of P3HT and PSLG were the main driving force for P3HT chain ordering into the crystalline assemblies. It was found that the orientation of rigid P3HT fibrils on the substrate adopted the directionality of the evaporating front. Regardless of the PSLG-coated particle dimensions used, the drop-cast films displayed patterns that were shaped by the coffee ring and Marangoni effects. PSLG-coated particles of high axial ratio (4.2) were more efficient in enhancing the electronic performance of P3HT than low axial ratio (2.6) homologues. Devices fabricated from the ordered assemblies displayed improved charge-carrier transport performance when compared to devices fabricated from P3HT alone. These results suggest that PSLG can favorably mediate the organization of semiconducting polymers.