Water stable, antimicrobial active nanofibres generated by electrospinning from aqueous spinning solutions

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. ...