Pseudo-tricolor typed nanobelts and arrays simultaneously endowed with conductive anisotropy, magnetism and white fluorescence

Abstract

A novel [uniaxial needle]//[coaxial needle]//[uniaxial needle] parallel spinneret is first innovatively designed and manufactured by inserting a coaxial needle into the middle of a bi-axial parallel needle, and the corresponding spinning device is established. With the aid of the distinctive-structured spinneret and the spinning device, a novel and brand-new flexible one-dimensional nanobelt//coaxial nanobelt//nanobelt tri-strand parallel nanobelt, very much like a tricolor flag and named a pseudo-tricolor typed nanobelt, is successfully prepared by electrospinning technology for the first time. Microscopically, partition of four independent domains in the pseudo-tricolor typed nanobelt is realized, and such a partitioned structure can assemble various functions and helps reduce detrimental interactions among various functions to acquire excellent poly-functions of multifunctional nanomaterials. As a case study, {anthracene/Eu(2-thenoyltrifluoroacetone)₃(triphenylphosphine oxide)₂ [Eu(TTA)₃(TPPO)₂]/polymethylmethacrylate (PMMA)}//{[CoFe₂O₄/PMMA]@[polyaniline (PANI)/PMMA]}//{coumarin-6/PMMA} pseudo-tricolor typed nanobelts and arrays (abbreviated as [B + R]//[M@C]//[G] PNA) are designed and constructed via electrospinning. Each pseudo-tricolor typed nanobelt is composed of left and right sides of blue and red fluorescent [anthracene/Eu(TTA)₃(TPPO)₂/PMMA] nanobelts and green fluorescent [coumarin-6/PMMA] nanobelts, respectively, and the middle of the [CoFe₂O₄/PMMA]@[PANI/PMMA] coaxial nanobelt with magnetic-conductive bifunctionality using the CoFe₂O₄/PMMA nanobelt as the core and PANI/PMMA as the shell. Luminescence-magnetic-conductive polyfunctionalities are highly integrated but also mutually separated in the pseudo-tricolor typed nanobelt, and thus, both segregation and integration of the functions are actualized in the pseudo-tricolor typed nanobelt. A pseudo-tricolor typed nanobelt as the building unit ensures strong fluorescence and high conductive anisotropy of the array. Moreover, energy transfer between dyes is controlled by the special structure of the nanobelt and thus white light emission is realized by the combination of europium complexes with the dyes. The conductive anisotropy and magnetism of the array are tuned by changing the content of PANI and CoFe₂O₄, respectively. The formation mechanism of the pseudo-tricolor typed nanobelt is proposed, and new techniques for constructing nanobelts and arrays are established. This kind of pseudo-tricolor typed nanobelt with four functional subareas possesses important implications as a building unit to construct other polyfunctional nanostructures. More importantly, the design philosophy and the construction techniques for the novel pseudo-tricolor typed nanobelt and array afford some guidance for the development of other multifunctional materials.