Matrix Effect on Polydiarylfluorenes Electrospun Hybrid Microfibers: From Morphology Tuning to High Explosive Detection Efficiency

Precisely optimizing the morphology of functional hybrid polymeric systems is crucial to improve its photophysical property and further extend their optoelectronic applications. The physic-chemical property of polymeric matrix in electrospinning (ES) processing is a key factor to dominate the condensed structure of these hybrid microstructures and further improve its functionality. Herein, we set a flexible poly(ethylene oxide) (PEO) as the matrix to obtain a series of polydiarylfluorenes (including PHDPF, PODPF and PNDPF) electrospun hybrid microfibers with a robust deep-blue emission. Significantly different from the rough morphology of their poly(N-vinylcarbazole) (PVK) ES hybrid fibers, polydiarylfluorenes/PEO ES fibers showed a smooth morphology and small size with a diameter of 1∼2 µm. Besides, there is a relatively weak phase separation under rapid solvent evaporation during the ES processing, associated with the hydrogen-bonded-assisted network of PEO in ES fibers. These relative “homogeneous” ES fibers present efficient deep-blue emission (PLQY>50%), due to weak interchain aggregation. More interestingly, low fraction of planar (β) conformation appears in the uniform PODPF/PEO ES fibers, induced by the external traction force in ES processing. Meanwhile, PNDPF/PEO ES fibers present a highest sensitivity than those of other ES fibers, associated with the smallest diameter and large surface area. Finally, compared to PODPF/PVK fibers and PODPF/PEO amorphous ES fibers, PODPF/PEO ES fibers obtained from DCE solution exhibit an excellent quenching behavior toward a saturated DNT vapor, mainly due to the synergistic effect of small size, weak separation, β-conformation formation and high deep-blue emission efficiency.

Electrospun Supramolecular Hybrid Microfibers from Conjugated Polymers:Color Transformation and Conductivity Evolution

A type of novel electrospun supramolecular hybrid microfibers comprising poly(9-(4-(octyloxy)-phenyl)-2,7-fluoren-9-ol)(PPFOH)and poly(A/-vinylcarbazole)(PVK)are successfully prepared for intriguing multi-color emission properties.The supramolecular tunable PPFOH aggregation in PVK matrix endows the complex with a smart energy transfer behavior to obtain the multi-color emissions.In stark contrast to PVK fibers,the emission color of PPFOH/PVK fibers with an efficient dispersion of PPFOH fluorophores at a proper dope ratio can be tuned in a wide spectrum of blue(0.1%),sky blue(0.5%),nearly white(1%),cyan(2%),green(5%)and yellow(10%).Besides,conductive behaviors of the microfiber were demonstrated in accompany with the increment of the doping ratio of PPFOH to PVK.Successful fabrication of polymer light-emitting diode(PLED)based on the blended electrospun fiber provided a further evidence of its excellent electrical property for potential applications in optoelectronic devices.