Development of multifunctional modified cotton fabric with tri-component nanoparticles of silver, copper and zinc oxide.

A facile method, cost-effective and highly efficient with shortened-time operation was devised for unprecedented modification of cotton fabrics. This modification induced the formation of metallic and metal oxide nanoparticles within cotton fabrics in such a way that cotton samples loaded with AgNPs- or AgNPs/ZnONPs or AgNPs/ZnONPs/CuNPs respectively. Presence of the trimetallic nanoparticles concomitantly within microstructural features of cotton imparts durable antibacterial, UV protection and conductivity properties to yield ultimately cotton fabrics with multifunctional performance. The nanoparticles were formed and stabilized independently by Polymethylol compound (PMC) and functionalized polyethyleneimine (FPEI) as per one bath. The results obtained proved that the solution of these metal compounds are turned from colourless to yellow and black green colour up on addition of PMC or FPEI compound. It was found that UV-vis spectra display maximum surface plasmon peak of around 410-415 confirming the successful synthesis of AgNPs stabilized by PMC or FPEI chains. In addition, the results obtained indicated that the as formed nanoparticles are successfully deposited into the surface of cellulose fabrics and reveal changes in crystalline structure. Fabrics underwent structural changes during their treatments as per the designed practice exhibit multifunctional properties and manifold performance. The resultant treated cotton fabric gives good antibacterial properties event after 20 washing cycles additionally to the excellent ultra-violet properties and excellent electrical conductivity.

Eco-friendly microwave-assisted green and rapid synthesis of well-stabilized gold and core-shell silver-gold nanoparticles.

Herein, we present a new approach for the synthesis of gold nanoparticles (AuNPs) individually and as bimetallic core-shell nanoparticles (AgNPs-AuNPs). The novelty of the approach is further maximized by using curdlan (CRD) biopolymer to perform the dual role of reducing and capping agents and microwave-aided technology for affecting the said nanoparticles with varying concentrations in addition to those affected by precursor concentrations. Thus, for preparation of AuNPs, curdlan was solubilized in alkali solution followed by an addition of tetrachloroauric acid (HAuCl4). The curdlan solution containing HAuCl4 was then subjected to microwave radiation for up to 10 min. The optimum conditions obtained with the synthesis of AuNPs were employed for preparation of core-shell silver-gold nanoparticles by replacing definite portion of HAuCl4 with an equivalent portion of silver nitrate (AgNO3). The portion of AgNO3 was added initially and allowed to be reduced by virtue of the dual role of curdlan under microwave radiation. The corresponding portion of HAuCl4 was then added and allowed to complete the reaction. Characterization of AuNPs and AgNPs-AuNPs core-shell were made using UV-vis spectra, TEM, FTIR, XRD, zeta potential, and AFM analysis. Accordingly, strong peaks of the colloidal particles show surface plasmon resonance (SPR) at maximum wavelength of 540 nm, proving the formation of well-stabilized gold nanoparticles. TEM investigations reveal that the major size of AuNPs formed at different Au(+3)concentration lie below 20 nm with narrow size distribution. Whilst, the SPR bands of AgNPs-AuNPs core-shell differ than those obtained from original AgNPs (420 nm) and AuNPs (540 nm). Such shifting due to SPR of Au nanoshell deposited onto AgNPs core was significantly affected by the variation of bimetallic ratios applied. TEM micrographs show variation in contrast between dark silver core and the lighter gold shell. Increasing the ratio of silver ions leads to significant decrease in zeta potential of the formed bimetallic core-shell. FT-IR discloses the interaction between CRD and metal nanoparticles, which could be the question of reducing and stabilizing metal and bimetallic nanoparticles. XRD patterns assume insufficient difference for the AuNPs and AgNPs-AuNPs core-shell samples due to close lattice constants of Ag and Au. Based on AFM, AuNPs and AgNPs-AuNPs core-shell exhibited good monodispersity with spherical particles possessing different sizes in the studied samples. The average sizes of both metal and bimetallic core-shell were found to be 52 and 45 nm, respectively.

Utilization of chitosan nanoparticles as a green finish in multifunctionalization of cotton textile.

Chitosan nanoparticles were synthesized through polymerization of CS at different concentrations with methacrylic acid (MAA) using K2S2O8 as initiator. This polymerization gave rise to suspension which was ice-cooled then subjected to severe centrifuging and the supernatant discarded to yield CS nanoparticles. Major characteristics of the so prepared CS nanoparticles namely size/distribution of the particles, their structural features, surface description and thermal stability were examined using DLS, FTIR, SEM and TGA, respectively. When CS nanoparticles were used as a finish for cotton fabrics with a crosslinking agent, the fabric displayed improved dyeability and thermal stability as well as antibacterial activity and UV protection. These latter two functionalities were significantly increased by post treatment of fabric with copper sulfate.

Development of CMC hydrogels loaded with silver nano-particles for medical applications.

Innovative CMC-based hydrogels with great potentials for usage in medical area were principally synthesized as per two strategies .The first involved reaction of epichlorohydrin in alkaline medium containing silver nitrate to yield silver nano-particles (AgNPs)-loaded CMC hydrogel. While CMC acted as stabilizing for AgNPs, trisodium citrate was added to the reaction medium to assist CMC in establishing reduction of Ag(+) to AgNPs. The second strategy entailed preparation of CMC hydrogel which assists the in situ preparation of AgNPs under the same conditions. In both strategies, factors affecting the characterization of AgNPs-loaded CMC hydrogels were studied. Analysis and characterization of the so obtained hydrogels were performed through monitoring swelling behavior, FTIR spectroscopy, SEM, EDX, UV-vis spectrophotometer and TEM. Antimicrobial activity of the hydrogels was examined and mechanisms involved in their synthesis were reported.