Synthesis of functional polymers by chemical modification of PECH and PECH–PEO with substituted phenolates

Synthesis, Characterization, and Applications of Silver Nano Fibers in Humidity, Ammonia, and Temperature Sensing

The promising chemical, mechanical, and electrical properties of silver from nano scale to bulk level make it useful to be used in a variety of applications in the biomedical and electronic fields. Recently, several methods have been proposed and applied for the small-scale and mass production of silver in the form of nanoparticles, nanowires, and nanofibers. In this research, we have proposed a novel method for the fabrication of silver nano fibers (AgNFs) that is environmentally friendly and can be easily deployed for large-scale production. Moreover, the proposed technique is easy for device fabrication in different applications. To validate the properties, the synthesized silver nanofibers have been examined through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Further, the synthesized silver nanofibers have been deposited over sensors for Relative humidity (RH), Ammonia (NH3), and temperature sensing applications. The sensor was of a resistive type, and found 4.3 kΩ for relative humidity (RH %) 30-90%, 400 kΩ for NH3 (40,000 ppm), and 5 MΩ for temperature sensing (69 °C). The durability and speed of the sensor verified through repetitive, response, and recovery tests of the sensor in a humidity and gas chamber. It was observed that the sensor took 13 s to respond, 27 s to measure the maximum value, and took 33 s to regain its minimum value. Furthermore, it was observed that at lower frequencies and higher concentration of NH3, the response of the device was excellent. Furthermore, the device has linear and repetitive responses, is cost-effective, and is easy to fabricate.

Environmental fate and effect of biodegradable electro-spun scaffolds (biomaterial)-a case study

Poly-ε-caprolactone (PCL) based medical devices are increasingly produced and thus, their presence in the environment is likely to increase. The present study analysed the biodegradation of PCL electro-spun scaffolds (alone) and PCL electro-spun scaffolds coated with human recombinant (hR) collagen and Bovine Achilles tendon (BAT) collagen in sewage sludge and in soil. Additionally, an eco-toxicological test with the model organism Enchytraeus crypticus was performed to assess environmental hazard of the produced materials in soils. The electro-spun scaffolds were exposed to activated sludge and three different soils for various time periods (0-7-14-21-28-56-180 days); subsequently the degradation was determined by weight loss and microscopical analysis. Although no toxicity occurred in terms of Enchytraeus crypticus reproduction, our data indicate that biodegradation was dependent on the coating of the material and exposure condition. Further, only partial PCL decomposition was possible in sewage treatment plants. Collectively, these data indicate that electro-spun PCL scaffolds are transferred to amended soils.