This dissertation is concerned about the development of antimicrobial active nanofibres. The objective was to generate these nanofibres from aqueous spinning solutions via electrospinning. By this, organic solvents were avoided so that electrospinning was performed at environmentally friendly conditions. Electrospinning of aqueous spinning solutions necessitated the application of water soluble polymers so that the gained nanofibres exhibited nearly no water stability. Further content of this thesis was therewith the development of different stabilisation techniques for the nanofibres. The formation of antimicrobial poly(vinyl alcohol) (PVA) nanofibre webs containing spherical nano-Ag via electrospinning with special regard to utilise these nanofibres in filter media was studied. Aqueous PVA solutions with addition of silver nitrate were electrospun. Afterwards, the gained nanofibres were UV irradiated in order to reduce the silver ions within the fibre matrix to elemental nano-sized silver. The resulting nanofibre webs were stabilised towards aqueous surroundings by a heat induced crystallisation. Furthermore, the influence of spinning and solution parameters on the resulting fibre morphology was investigated and antimicrobial functionality of the nanofibres was proven. Here, the minimum efficient nano-Ag content as well as the release behaviour of silver ions from the fibre matrix in comparison to that of silver salts was studied. The nanofibres were examined concerning their potential usage in filters by electrospinning them directly on support fleeces and application of standardised test dust onto the nanofibre webs. Thereby, the deposition behaviour of the test dust on the nanofibres and its potential impact on antimicrobial activity were investigated. In the next chapter, PVA nanofibres were provided with the quaternary ammonium silane 3 (trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (TMS QAC18) in order to achieve i) antimicrobial activity and ii) water stability of the nanofibres. Homogeneous PVA/TMS-QAC18 composite nanofibres were generated by electrospinning of an aqueous PVA solution with addition of TMS-QAC18. Furthermore, as second method coating of pure PVA nanofibres with the organosilane was performed. The organosilane was permanently bond to the PVA by heat treatment of the nanofibres. Thereby, the surface properties of the fibres changed. Inhibition of the bacterial growth of B.subtilis was proven, though the fibre webs exhibited no significant antimicrobial effect on E.coli. Furthermore, water stabilities of the nanofibre webs were investigated. In the following chapter, three different photo-induced chemical crosslinking strategies for PVA nanofibres were investigated. Crosslinking was performed i) by formation of a semi-interpenetrating network consisting of poly(ethylene glycol)dimethacrylate (PEGDMA) within the PVA matrix, ii) in the presence of sodium benzoate as sensitizer and iii) by previous reaction of PVA with glycidyl methacrylate (GMA) resulting in a crosslinkable and electrospinnable product (PVA-MA). All strategies were optimised, investigated and examined with regard to their efficiency for stabilisation of the nanofibres towards water. Furthermore PVA/silica hybrid nanofibres were prepared by electrospinning. The inorganic/organic hybrid fibres possessed excellent intrinsic water stability. The spinning process was optimised regarding the fibre diameter and homogeneity. Ag-nanoparticles were incorporated into the fibre matrix in order to achieve antimicrobial activity. For that, silver nitrate was used as add-on to the spinning solution and subsequently reduced by UV-irradiation within the electrospun fibres to elemental, spherical nanoparticles. Antimicrobial activity of these fibres against E.coli and B.subtilis was proven. Fibres were tested for thermal stability. Exposed to high temperature the nano-Ag exhibited changed particle morphology and reduced antimicrobial activity. In last chapter, PVA/silica hybrid nanofibres were provided with TiO2 nanoparticles; the hybrid nanofibres were gained from an aqueous silica sol/PVA mixture without usage of organic solvents. The TiO2 particles were deposited onto the fibres’ surface subsequently electrospinning. For that, an aqueous, commercial available TiO2 dispersion (VP Disp. W740X, Degussa) was sprayed onto the nanofibre webs. For the TiO2-equipped PVA/silica nanofibres a good photocatalytic activity was proven. Additionally, pure silica nanofibres were prepared from a silica sol-gel and also equipped with TiO2-particles at the same procedure. Attachment and binding durability of TiO2 particles onto both fibre types were investigated by electron microscopy (FESEM, TEM). Thereby, for the hybrid nanofibres good durability of TiO2 was attested whereas nearly no attachment of the particles onto the silica nanofibres could be detected.
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