Porous, Aligned, and Biomimetic Fibers of Regenerated Silk Fibroin Produced by Solution Blow Spinning.

Solution blow spinning (SBS) has emerged as a rapid and scalable technique for the production of polymeric and ceramic materials into micro-/nanofibers. Here, SBS was employed to produce submicrometer fibers of regenerated silk fibroin (RSF) from Bombyx mori (silkworm) cocoons based on formic acid or aqueous systems. Spinning in the presence of vapor permitted the production of fibers from aqueous solutions, and high alignment could be obtained by modifying the SBS setup to give a concentrated channeled airflow. The combination of SBS and a thermally induced phase separation technique (TIPS) resulted in the production of macro-/microporous fibers with 3D interconnected pores. Furthermore, a coaxial SBS system enabled a pH gradient and kosmotropic salts to be applied at the point of fiber formation, mimicking some of the aspects of the natural spinning process, fostering fiber formation by self-assembly of the spinning dope. This scalable and fast production of various types of silk-based fibrous scaffolds could be suitable for a myriad of biomedical applications.

One-Volt, Solution-Processed Organic Transistors with Self-Assembled Monolayer-Ta2O5 Gate Dielectrics.

Low-voltage, solution-processed organic thin-film transistors (OTFTs) have tremendous potential to be key components in low-cost, flexible and large-area electronics. However, for these devices to operate at low voltage, robust and high capacitance gate dielectrics are urgently needed. Herein, the fabrication of OTFTs that operate at 1 V is reported. These devices comprise a solution-processed, self-assembled monolayer (SAM) modified tantalum pentoxide (Ta2O5) as the gate dielectric. The morphology and dielectric properties of the anodized Ta2O5 films with and without n-octadecyltrichlorosilane (OTS) SAM treatment have been studied. The thickness of the Ta2O5 film was optimized by varying the anodization voltage. The results show that organic TFTs gated with OTS-modified tantalum pentoxide anodized at 3 V (d ~7 nm) exhibit the best performance. The devices operate at 1 V with a saturation field-effect mobility larger than 0.2 cm2 V-1 s-1, threshold voltage -0.55 V, subthreshold swing 120 mV/dec, and current on/off ratio in excess of 5 × 103. As a result, the demonstrated OTFTs display a promising performance for applications in low-voltage, portable electronics.