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We report multiscale structured fibers and patterned films based on a semiconducting polymer, poly(3-hexylthiophene) (P3HT), as photoconductive biointerfaces to promote neuronal stimulation upon light irradiation. The micro/nanoscale structures of P3HT used for neuronal interfacing and stimulation include nanofibers with an average diameter of 100 nm, microfibers with an average diameter of about 1 μm, and lithographically patterned stripes with width of 3, 25, and 50 μm, respectively. The photoconductive effect of P3HT upon light irradiation provides electrical stimulation for neuronal differentiation and directed growth. Our results demonstrate that neurons on P3HT nanofibers showed a significantly higher total number of branches, while neurons grown on P3HT microfibers had longer and thinner neurites. Such a combination strategy of topographical and photoconductive stimulation can be applied to further enhance neuronal differentiation and directed growth. These photoconductive polymeric micro/nanostructures demonstrated their great potential for neural engineering and development of novel neural regenerative devices.

High-mobility organic thin film transistors based on a benzobisthiadiazole-containing polymer are presented together with their morphological and optical properties. A very tight packing pattern of "edge-on" orientated polymer chains is observed in their thin films after annealing, and the hole mobility of this polymer is up to 2.5 cm(2) V(-1) s(-1) ., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High mobility ambipolor organic thin-film transistors based on an ultralow bandgap polymer are presented together with their morphological and optical properties. Hole and electron mobilities of this polymer are of 1.0 cm(2) V(-1) s(-1) and 0.7 cm(2) V(-1) s(-1), respectively. The inverter based on two identical ambipolar transistors exhibits a gain around 35., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The effect of molecular self-assembly on nanoscale photoinduced charge generation of fullerene-capped poly(3-hexylthiophene) (PCB-c-P3HT) films and its effectiveness as a molecular additive in bulk heterojunction P3HT:[6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) is investigated through photoconductive atomic force microscopy. ortho-Dichlorobenzene-cast films of PCB-c-P3HT are found to form interconnected fibrous networks that show high photocurrent generation, while tetrahydrofuran-cast films show nanospheres with relatively low photocurrent generation. The nanofiber size and current generated from these nanowires are shown to vary with additions of PCBM. The PCB-c-P3HT amphiphile is shown to be a successful molecular additive in P3HT:PCBM films. These observations demonstrate how the self-assembly of PCB-c-P3HT into specific nanostructures is crucial to charge generation and transport.

ABSTRACT Direct arylation polymerization between derivatives of dibromodiketopyrrolopyrrole (DPP) and thienoisoindigo (TIIG) resulted in two π-conjugated copolymers with average molecular weights up to 24.0 kDa and bandgaps as low as 0.8 eV. The structural analysis of the obtained two polymers revealed well-defined alternating conjugation backbones without obvious structural defects. The introduction of hexyl-group in the β-position of thiophene rings in the DPP units not only reduces the bandgap of conjugated polymer compared to a similar polymer containing bare-thiophene flanked DPP but also affects polymer morphology in thin films. P-type charge-transport characteristics were observed for two polymers in organic field-effect transistors with comparable hole mobilities. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3205-3213 [ABSTRACT FROM AUTHOR]

ABSTRACT Well-defined 1,4-diketo-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole (DTDPP) labeled polycaprolactones (PCL) with different chain lengths were synthesized and characterized. The effect of polymer chain lengths on the optical properties of DTDPP in solid states was studied by UV-Vis absorption spectroscopy as well as steady-state and dynamic fluorescence spectroscopies. Our results indicate that when the PCL side chain is extended to a certain length, the intermolecular aggregation of DTDPP units can be reduced significantly due to segregation effect of PCL. This approach offers a new facile strategy to address the common problem of aggregation-caused quenching existing in organic fluorophores. These highly fluorescent biodegradable PCL polymers may find broad biomedical applications such as fluorescence-based bioimaging and tissue engineering. © 2015 Wiley Periodicals, Inc. J. Polym. Sci. Part A: Polym. Chem. 2015, 53, 1032-1042 [ABSTRACT FROM AUTHOR]

Photothermal therapy has emerged as a promising tool for treatment of diseases such as cancers. Previous photothermal agents have been largely limited to inorganic nanomaterials and conductive polymers that are barely biodegradable, thus raising issues of long-term toxicity for clinical applications. Here we report a new photothermal agent based on colloidal nanoparticles formed by a small-molecular dye, benzo[1,2-c;4,5-c′]bis[1,2,5]thiadiazole-4,7-bis(5-(2-ethylhexyl)thiophene). These nanoparticles showed strong near-infrared absorption, robust photostability and high therapeutic efficiency for photothermal treatment of cancer cells. [ABSTRACT FROM AUTHOR]