(217fj) Controlled Gelation of Poly(3-alkylthiophene)s in Bulk and Thin Film Environments Using Low Volatility Solvent/Non-Solvent Mixtures

Organic electronic devices such as organic photovoltaics (OPVs) and field effect transistors (OFETs) represent emerging commercial technologies that rely heavily on efficient charge transport through an interconnected network structure. One way to systematically engineer this network structure is the through the self-assembly and gelation of conjugate polymers.[1-2] This work demonstrates the potential to control the multi-length scale structure of poly(3-alkylthiophene) (P3AT) gel networks using a solvent/non-solvent combination to control the driving force for self-assembly. Structure-property relationships are developed through the simultaneous use of small angle neutron scattering (SANS), rheology and dielectric spectroscopy during the intermediate stages of self-assembly. The relationships developed within the bulk system are then applied to thin film gelation. The low-volatility mixture of solvents allows for thermoreversible gelation within a confined thin film. This thin film gelation process represents a new route towards developing interconnected network structures that can be utilized in organic electronic devices.

References:

[1] – Newbloom, G. M.; Weigandt, K. M.; Pozzo, D. C., “Electrical, Mechanical, and Structural Characterization of Self-Assembly in Poly(3-hexylthiophene) Organogel Networks” Macromolecules 2012, 45, (8), 3452-3462.

[2] – Newbloom, G. M.; Weigandt, K. M.; Pozzo, D. C., “Structure and Property Development of Poly(3-hexylthiophene) Organogels Probed with Combined Rheology, Conductivity and Small Angle Neutron Scattering” Soft Matter 2012, 8, (34), 8854-8864.