02317nas a2200217 4500008004100000022001400041245011300055210006900168260006900237300001200306490000800318520148300326653002101809653002901830653001701859653002401876100002301900700003001923700002301953856012301976 2012 eng d a1385-894700aSegmented flow synthesis of Ag nanoparticles in spiral microreactor: role of continuous and disperzsed phase0 aSegmented flow synthesis of Ag nanoparticles in spiral microreac aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcJUN a357-3680 v1923 a

This work focuses on understanding the effect of segmented flow on the nanoparticle size distribution in a unidirectionally expanding spiral microreactor, where secondary flows are prevalent in the absence of segmentation. Stearic acid sophorolipid reduced/capped Ag NPs were synthesized in the aqueous phase and air or kerosene was used as inert phases for creating the gas-liquid and liquid-liquid segmented flow, respectively. While, in one case the reactant phase is in the form of dispersed phase slugs, in the other case it is in the form of continuous phase, each exhibiting a different behavior. The slug sizes and the slip velocity, both of which govern the nature of internal mixing in the reactant phase slug controlled the nanoparticle size distribution. This observation was consistent for both, gas-liquid and liquid-liquid segmented flows. The micromixer having smaller orifice diameter yielded smaller slugs and also a narrow particle size distribution. In general, the particle sizes were much smaller for gas-liquid flow rather than for liquid-liquid flow. Because of the unidirectionally expanding spiral geometry of the channel, at any given condition, unsteady behavior of slugs due to continuously varying radius of curvature results in variation in the slip velocity along the length of microchannel. This effect was seen to further narrow the particle size distribution than alone by the segmented flow. (C) 2012 Elsevier B.V. All rights reserved.

10aAg nanoparticles10aSegmented flow synthesis10aSophorolipid10aSpiral microreactor1 aKumar, D., V. Ravi1 aPrasad, Bhagavatula L. V.1 aKulkarni, Amol, A. uhttps://library.ncl.res.in/content/segmented-flow-synthesis-ag-nanoparticles-spiral-microreactor-role-continuous-and-001572nas a2200205 4500008004100000022001400041245012600055210006900181260011000250300001600360490000600376520070600382100002301088700002001111700002601131700002601157700002101183700003001204856013201234 2013 eng d a2046-206900aSurfactant-free synthesis of anisotropic gold nanostructures: can dicarboxylic acids alone act as shape directing agents?0 aSurfactantfree synthesis of anisotropic gold nanostructures can  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAUG a21641-216470 v33 a

The present study describes the synthesis of gold nanostructures using different dicarboxylic (viz. oxalic, malonic, succinic, glutaric and adipic) acids as reducing agents in the absence of any other additives or surfactants. Various anisotropic structures such as kites, tadpoles, triangular/hexagonal plates, and twinned particles were seen to evolve depending on the molar ratio of dicarboxylic acid to HAuCl4 used. It was also demonstrated that gold nanostructure formation is hampered as the chain length/distance between two carboxylic acid groups increases. Among the various structures obtained the kite like structures displayed the largest surface enhanced Raman enhancement factors.

1 aKumar, D., V. Ravi1 aKumavat, S., R.1 aChamundeswari, V., N.1 aPatra, Partha, Pratim1 aKulkarni, A., A.1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/surfactant-free-synthesis-anisotropic-gold-nanostructures-can-dicarboxylic-acids-alone-act-002045nas a2200253 4500008004100000022001400041245008100055210006900136260007300205300001200278490000800290520113200298653002101430653002201451653001801473653002701491653003701518653002601555653002301581100002301604700002301627700003001650856011101680 2013 eng d a0927-775700aSynthesis of triangular gold nanoplates: role of bromide ion and temperature0 aSynthesis of triangular gold nanoplates role of bromide ion and  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR a181-1900 v4223 a

Synthesis of noble metal triangular nanoplates is a kinetically controlled process in which temperature and packing defects play a major role. Nucleation and growth process of kinetically controlled reaction can be greatly influenced by temperature affecting the yield and edge length of the triangles. Through a conventional batch mode process, here we study the effect of temperature on nucleation and growth of gold triangular nanoplates and obtain some insight of the temperature effects on the final yield and edge length of triangles. The role of Br- ions in the synthesis of triangular nanoplates is studied by varying the amount of CAB and by replacing the CTAB with HBr. The results show that, while CTAB controls the edge length and yield of triangles, its use is not mandatory to attain plate like morphology. Finally we show that, while the initial temperature of the reaction mixture governs the nucleation rate and the rate of temperature rise governs the growth rate of particles, they along with the concentration of Br- ions control the edge length and yield. (C) 2013 Elsevier B.V. All rights reserved.

10aAu nanotriangles10aHalide ion effect10aheat transfer10aKinetically controlled10aNature of gold precursor complex10aNucleation and growth10aOptical properties1 aKumar, D., V. Ravi1 aKulkarni, Amol, A.1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/synthesis-triangular-gold-nanoplates-role-bromide-ion-and-temperature-0