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In this study, we report a simple and green method for the synthesis of l-tyrosine-stabilized silver (AgNPs) and gold nanoparticles (AuNPs) in aqueous medium under ambient sunlight irradiation. The nanoparticles (NPs) are characterized by UV–visible spectroscopy, high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), and dynamic light scattering (DLS) techniques. The size and shape of the metal NPs could be controlled by changing the concentration of the substrate, metal precursors, and pH of the medium. The synthesized AgNPs are found to be highly sensitive to Hg2+ and Mn2+ ions with the detection limit for both ions as low as 16 nM under optimized conditions. However AuNPs are found to be sensitive to Hg2+ and Pb2+ ions with a detection limit as low as 53 and 16 nM, respectively. The proposed method was found to be useful for colorimetric detection of heavy metal ions in aqueous medium.

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In this article, three test methods are described to measure the water spreading behaviour of textiles such as rate of absorbency and total absorbent capacity. The methods described are manual method, commercial image analysis method using Photoshop and embedded image analysis method using digital signal processor through MATLAB software (EIAS). With these methods the rate of absorbency and total water absorbent capacity were analysed in 12 different knitted/woven fabrics. In order to compare the three test methods, the correlation among the methods were analysed. A very good correlation (more than 0.9) was found between the manual water spreading tests and commercial image analysis method using Photoshop when compared to manual versus EIAS method. Also Photoshop versus EIAS method correlation was found better than manual versus EIAS method.

pH-Sensitive interpenetrating network (IPN) microgels (MGs) of sodium alginate (NaAlg) and acrylic acid have been prepared by using water-in-oil (W/O) emulsion technique. The MGs were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffractometer (X-RD). The release of ibuprofen (IB), an anti-inflammatory drug, from these MGs was studied in pH 1.2 and 7.4 media. MG network consists of NaAlg, which disintegrates in the intestinal fluid, while poly(acrylic acid) provides pH-sensitivity to the microgel network. The system developed in this study showed a pH-sensitivity for the release of IB, which was attributed to the diffusion controlled release of the drug through the surfaces of MGs that undergo disintegration after swelling, depending upon the chemical composition of MGs and pH of the medium.

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