Synthesis and characterization of hydrophobic, ultra-fine fibres based on an organic–inorganic nanocomposite containing a polyimide functionality

Abstract

Ultra-thin polyimide fibres were fabricated by means of the electrospinning method by using precursor solutions consisting of the organotrialkoxysilanes (3-triethoxysilylpropyl)succinic anhydride (TESP-SA), (3-amino)propyltriethoxysilane (APTES), tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS). TESP-SA and APTES were reacted to the corresponding poly(amic)acid (PAA) in an aqueous medium which was electrospun at 15 kV and at a tip to collector distance of 15 cm. TEOS and MTEOS were also incorporated into the precursor solution to modify the surface properties of the ultra-fine fibre mat. The fibre diameter distributions of the as-prepared PAA fibres were measured. The PAA fibres were thermally treated at 220 C resulting in the formation of an organic-inorganic hybrid polyimide fibre mat with ladderlike structure, as could be shown by Fourier transform infrared spectroscopy and X-ray powder diffraction. The ultra-fine fibre assemblies were also characterized by means of scanning electron microscopy, thermogravimetric analysis and water contact angle measurements.

Pure hybrid nanofibers made of 4,4′-bis(triethoxysilyl)-1,1′-biphenyl and the way of their production

“…Until 2021, only five solitary research papers regarding the preparation of the purely hybrid organic-inorganic organosilane nanofibers were published. [35][36][37][38][39] Mentioned nanofibers were prepared by three independent groups Tao et al [35], Schramm et al [36,37], and Máková et al [38,39]. The fibrous materials prepared by Tao et al [35] were mainly composed of an inorganic component based on tetraethyl orthosilicate (TEOS).…”

“…Moreover, this surfactant remained inside the prepared hybrid fibers. The third group, Máková et al [38,39], successfully prepared the first types of hybrid organicinorganic nanofibers in a significantly higher molar ratio of hybrid precursors inside the silica dioxide matrix compared to the other two research groups [35][36][37]. They were able to use hybrid precursors based on 1,4-bis(triethoxysilyl)benzene and triethoxyphenylsilane, with the molar ratio reaching up to 40 mol % inside the hybrid matrix [39].…”

“…Their hybrid nanofibers contained only 10 −4 mol % of a porphyrin bridged organosilane unit compared to TEOS. On the contrary, Schramm et al[36] used slightly different processes for the formation of hybrid organosilane fibers. These fibers were prepared by co-condensation of (3-triethoxysilylpropyl)succinic anhydride (TESP-SA) with either tetraethoxysilane (TEOS) or methyltriethoxysilane (MTEOS) which were hydrolyzed and reacted subsequently with (3-amino)propyltriethoxysilane (APTES).…”