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This work describes systems for the functionalization of electrospun fibers and latex particles. In both cases the functionalization was carried out via ATRP. The materials were therefore equipped with ATRP-initiating groups. The initiator was embedded directly into the side-groups of the used polymers.
The first step was the syntheses of an in DMF soluble ATRP-macroinitiator that was spun to fibers with less than 500 nm in diameter.
In a further step these fibers were modified to receive thermoresponsive, pH-responsive, and antibacterial fibermats.
In order to receive thermoresponsive fibermats, P(NIPAm) was grafted from the surface of the macroinitiator fibers. Due to the LCST of P(NIPAm), the grafted fibers showed a temperature-depending wetting behavior. This was proven by contact angle measurements. Additionally, it was observed that grafting of P(NIPAm) lead to an increase of the fiberdiameter that was proportional to the grafting time.
pH-responsive fibermats were received by grafting of P(4VP) from the surface of the macroinitiator fibers. P(4VP)-grafted fibermats demonstrated a pH-depending macroscopic swelling and shrinking up to 70% in size.
Three different systems were applied for producing antibacterial fibers.
First system describes the deposition of antibacterial silver nanoparticles onto P(4VP)-grafted fibers. The particles were deposited by coordination of silver ions onto the P(4VP) surface and later reduced by using sodiumboronhydride.
The second system investigates the grafting reaction of an antibacterial polymer (P(DMAEMA)) from the surface of the macroinitiator fibers. These fibers were later quarternized by using ethylbromide to enhance the antibacterial activity.
The third system is based on the deposition of cationic latex particles onto the surface of anionically charged electrospun fibers. These three systems were tested against Escherichia coli bacteria. It was shown that all modified materials had a high antibacterial activity.
Further, the system of electrospun macroinitiator fibers was transferred to a system that could be processed from aqueous solutions. Therefore, butylacrylate latex particles containing ATRP-initiator and photo-crosslinker units were synthesized. The fibers were received by electrospinning of these latex particles in presence of polyvinylacohol as matrix polymer. After crosslinking water-stable fibermats were received. Furthermore, P(DMAEMA) was grafted from the surface of these fibermats. Finally, the work describes a modification of the latex particle dispersions. These modified latex particles were grafted with P(DMAEMA) and quarternized with ethylbromide. Later the quarternized particles were immobilized on a carrier material for ion chromatography. Chromatographic tests have shown that these materials are suitable for anion chromatography.