Effect of synthesis conditions on the morphology and crystal structure of biferroic Bi5Ti3FeO15

Citrate-stabilized spherical silver nanoparticles (Ag NPs) with d=8.25 1.25nm diameter were prepared and functionalized with l-cysteine (Cys) in aqueous dispersion. The nanosilver-cysteine interactions have been investigated by Raman and 1H NMR spectroscopy. The effect of pH on stability of biofunctionalized Ag NPs was investigated. The cysteine-capped nanosilver dispersions remain stable at higher pH (pH>7), while the degree of aggregation increased as the pH decreased. Below pH ?7, the characteristic surface plasmon band of bare silver nanoparticles was back-shifted from ?measuredbareAgNP=391 nm to ?measured1=387-391 nm, while the presence of a new band at ?measured2=550-600 nm was also observed depending on pH. Finite element method (FEM) was applied to numerically compute the absorption spectra of aqueous dispersions containing bare and cysteine-functionalized Ag NPs at different pH. Both the dynamic light scattering (DLS) measurements, Zeta potential values and the transmission electron microscopic (TEM) images confirmed our supposition. Namely, electrostatic interaction arose between the deprotonated carboxylate (COO -) and protonated amino groups (NH 3 +) of the amino acid resulting in cross-linking network of the Ag NPs between pH ?3 and 7. If the pH is measurable lower than ?3, parallel with the protonation of citrate and l-cysteine molecules the connection of the particles via l-cysteine is partly decomposed resulting in decrease of second plasmon band intensity. " 2012 Elsevier B.V.",,,,,,"10.1016/j.colsurfb.2012.03.036",,,"http://hdl.handle.net/20.500.12104/40984","http://www.scopus.com/inward/record.url?eid=2-s2.0-84861468429&partnerID=40&md5=403989d81bf95c0f723436c19354e1b9",,,,,,,,"Colloids and Surfaces B: Biointerfaces",,"4

Clusters of Poly(acrylates) and Silver Nanoparticles: Structure and Applications forAntimicrobial Fabrics

Silver−poly(acrylate) clusters have been synthesized in water by reduction of AgNO3 in the presence of poly(acrylates) of different molecular weights through two different methods, NaBH4 reduction and UV exposure. The structure of the clusters and the effect of the synthesis parameters on the size and polydispersity of the particles were evaluated by means of small-angle X-ray scattering (SAXS) and confirmed by UV−visible absorption and transmission electron microscopy (TEM). The results clearly show that the reduction method and the polymer chain length play key roles in the achievement of few-nanometer-sized nanoparticles. The effect of the pH was also investigated. The nanoparticle dispersions were then used to functionalize cotton, wool, and polyester samples in order to obtain antimicrobial textiles for biomedical applications. The antimicrobial activity of the as-treated samples has been tested against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Candida albicans