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Abstract

This thesis evaluates three novel synthesized conjugated polymer series with respect to their sensitivity and selectivity in the detection of nitroaromatic analytes, especially in aqueous environments. Central building blocks of the polymers are functionalized truxene or tetraphenylethene centers, which are polycondensed with different diethinylaromatics by Sonogashira cross- coupling. In a first explorative study, Truxene-based hyper-branched polymers (HCPs) were compared with related linear rod-shaped poly(p-phenylenethynylenes) (PPEs) with respect to their sensor performance of nitroaromatics (Chapter 2). By encapsulation with amphiphilic F-127 in water-soluble micelles, 14 nitroaromatics could be distinguished with 100% accuracy in fluorescence quenching experiments. The HCPs display a better sensor performance than the sensor system for nitroaromatics previously known from PPE (Chapter 2). To increase the sensor performance, tetraphenylethene cores (TPEs) replaced the truxene units in the polymers in a follow-up study (Chapter 3). TPEs use aggregate-induced emission to detect the analytes. A sensor field based on four TPE polymers was able to detect and distinguish nitroaromatics in water with excellent sensitivity (ppm range) compared to HCP or PPE systems (Chapter 3). This improved system is able to detect the regioisomers of nitroaromatics in a specific way. Finally, the performance of the TPE system was improved by varying the TPE moiety with amino or nitro groups for aqueous detection (Chapter 4). The functional TPE polymers (F-TPEPs) also exhibit aggregate-induced emission, with enhanced pH-specific (amino groups) or solvatochrome (nitro groups) sensor sensitivity. The presence of amino groups improves the sensory properties of F-TPEPs in the aqueous nitroaromatic system. The challenge of the detection of nitroaromatics in water could be mastered by the systematic development of F-TPEPs sensor system from the well-known PPE sensor.