(506h) Effect of Aging of P3HT Electrospinning Solution on the Processing Behavior and Fibers Properties

The electrospinning technique is an attractive route to process polymers in micro/nanofibers having potential applications in many areas. The electrospinning of poly(3-hexylthiophene) (P3HT) has been possible by adding a small amount of high molecular weight poly(ethylene oxide) in the spinning solution. Here, we present electrospinning of P3HT without (w/o) aging and with 24 h (w/24 h) aging of spinning solution at room temperature. Photoluminescence (PL) spectroscopic analysis indicates that self-assembly of P3HT chains took place during 24 h aging of the spinning solution, and this self-assembly process resulted in gelation. The gelation behavior was captured using shear rheometry experiments. The shear-rheometry data further indicate that shear stress in the needle during the spinning process dissociated the gel structure and led to the spinning of the gel sample. PL data captured distinct red-shift in fibers from the w/24 h aged solution compared with fibers from the w/o aging solution. This redshift implies that the self-assembly of P3HT chains in the aged spinning solution facilitated more ordering during electrospinning. The XRD data of the electrospun fibers obtained from the aged solution capture the noticeable change in crystallinity. GIWAXS analysis suggests the random orientation of polymer crystals with respect to the fiber axis. The average electrical conductivity of ~1.4*10^-5 S/cm was measured for a single electrospun fiber obtained from w/24 h aged solution of P3HT, which was higher than that obtained from w/o aged solution. Our results indicate that the structure and properties of electrospun conjugated fibers can be altered by changing the self-assembled structure of the polymer chains in the spinning solution.