02131nas a2200217   4500008004100000022001400041245009900055210006900154260009900223300001400322490000700336520130000343653001301643653001501656653002401671100002701695700002001722700002501742700001701767856012901784       2005                        eng d  a0032-386100aPolycondensation in liquid crystalline phases of nonionic surfactants. Kinetics and morphology0 aPolycondensation in liquid crystalline phases of nonionic surfac  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcSEP  a7961-79680 v463 a<p>We have investigated acid-catalyzed polycondensation of alkoxysilane monomers in liquid crystalline phases of nonionic CnEm surfactants. The liquid crystalline phase is retained when the monomers polymerize. The high molecular weight molecules formed phase separate from the mesophase and are subsequently organized by it to form micron-sized particles. A variety of particle morphologies are formed by organization of the polymer particles in the mesophase. For condensation of dimethyldimethoxysilane (DMS, with trimethoxysilane, TMS as crosslinker) in hexagonal and lamellar phases, specific reaction conditions, viz. slow condensation kinetics and low crosslink density, give rod-like particles in hexagonal phases and sheet-like structures in lamellar phases. However, when higher acid concentrations are used, the reaction kinetics accelerates and irregular particles form. Irregular particles also form when the fraction of trifunctional crosslinker is increased, and finally complex flower-like structures form for condensation of trimethoxysilane in the hexagonal phase. The particle morphology formed is crucially dependent on the details of the polycondensation rate, crosslinker density and surfactant-monomer/oligomer interactions. (c) 2005 Elsevier Ltd. All rights reserved.</p>10anonionic10asurfactant10atemplated synthesis1 aKumaraswamy, Guruswamy1 aWadekar, M., N.1 aAgrawal, Vikrant, V.1 aPasricha, R.  uhttps://library.ncl.res.in/content/polycondensation-liquid-crystalline-phases-nonionic-surfactants-kinetics-and-morphology-001695nas a2200181   4500008004100000022001400041245005900055210005900114260007100173300001400244490000700258520107100265100002001336700001701356700002001373700002701393856009301420       2005                        eng d  a0897-475600aPolymerization in surfactant liquid crystalline phases0 aPolymerization in surfactant liquid crystalline phases  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY  a2460-24650 v173 a<p>We report the formation of cross-linked polysiloxane particles having rodlike and sheetlike morphologies by condensation of monomers in organized liquid crystalline mesophases of nonionic surfactants. The characteristic diffraction pattern obtained from the liquid crystalline surfactant assembly is preserved during polymer synthesis. The polymer colloids are rodlike when synthesized in a hexagonal mesophase and are sheetlike when synthesized in a lamellar mesophase. Interestingly, the size of the polymer particles is on the order of micrometers, viz. 3 orders of magnitude larger than the characteristic size of the surfactant mesophase. Thus, the polymers phase separate from the liquid crystalline phase during polymerization, and organize to resemble the mesophase geometry. The polymer particles are organized so as to minimize the elastic distortion of the surfactant mesophase after they phase separate. We speculate that the observed particle morphologies are formed due to the slow kinetics of polycondensation under our experimental conditions.</p>1 aWadekar, M., N.1 aPasricha, R.1 aGaikwad, A., B.1 aKumaraswamy, Guruswamy  uhttps://library.ncl.res.in/content/polymerization-surfactant-liquid-crystalline-phases-001545nas a2200229   4500008004100000022001400041245005700055210005700112260007300169300001400242490000700256520082500263653001301088653002301101653002401124653002101148653001101169100001801180700001701198700001301215856008701228       2005                        eng d  a0167-577X00aPreparation of ferroelectric BaNb2O6 the urea method0 aPreparation of ferroelectric BaNb2O6 the urea method  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUN  a1929-19310 v593 a<p>A precipitate was formed when an aqueous solution of BaCl2, NbF5 and urea in required ratio (the ratio of total metal cations to the urea is five) is heated on a water bath at 100 degrees C. This precipitate on decomposition at 600 degrees C yielded the nanocrystallites of BaNb2O6 (BN), as confirmed by X-ray diffraction study (XRD). This is a much lower temperature as compared to that prepared by traditional solid state method (1000 degrees C) as reported for the formation of BaNb2O6. Transmission electron microscope (TEM) investigations revealed that the average particle size is 85 nm for the calcined powders. The room temperature dielectric constant at 1 kHz is found to be 900. The ferroelectric hysteresis loop parameters of these samples were also studied. (c) 2005 Elsevier B.V. All rights reserved.</p>10aCeramics10aChemical synthesis10aelectronic material10aferroelectricity10aOxides1 aDhage, S., R.1 aPasricha, R.1 aRavi, V.  uhttps://library.ncl.res.in/content/preparation-ferroelectric-banb2o6-urea-method-001441nas a2200193   4500008004100000022001400041245010300055210006900158260012500227300002300352490000700375520064400382100002901026700001701055700001701072700002001089700001301109856012501122       2006                        eng d  a0003-695100aPhysical manipulation of biological and chemical syntheses for nanoparticle shape and size control0 aPhysical manipulation of biological and chemical syntheses for n  aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScDEC  aArticle No. 2631050 v893 a<p>A nanosynthesis scheme is demonstrated which renders excellent control of nanoparticle shape, size, and dispersity in a solution based synthesis process. The scheme, termed as percolative microcavity synthesis, involves the use of a granular medium with percolative microcavities which facilitate nearly similar grain size/shape dependent reaction zones limiting intrinsic growth inhomogeneities, enabling particle size/shape control. The viability of the process is demonstrated for the synthesis of gold nanoparticles by a plant extract based biological method as well as a chemical method. (c) 2006 American Institute of Physics.</p>1 aOgale, Satishchandra, B.1 aAhmad, Absar1 aPasricha, R.1 aDhas, Vivek, V.1 aSyed, A.  uhttps://library.ncl.res.in/content/physical-manipulation-biological-and-chemical-syntheses-nanoparticle-shape-and-size-101611nas a2200289   4500008004100000022001400041245012700055210006900182260010600251300001400357490000700371520056300378653002200941653003200963653001400995653002701009653000801036100002201044700002001066700002401086700001701110700001901127700001801146700001601164700002201180856011901202       2006                        eng d  a1359-646200aPreparation of gamma-Fe2O3 nanoparticles using DC thermal arc-plasma route, their characterization and magnetic properties0 aPreparation of gammaFe2O3 nanoparticles using DC thermal arcplas  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcAPR  a1235-12400 v543 a<p>gamma-Fe2O3 particles were prepared, for the first time, using a direct current thermal arc-plasma route. The powder was characterized using X-ray diffraction, Mossbauer spectroscopy, X-ray photoelectron spectroscopy, chemical analysis, vibrating sample magnetometry C and transmission electron microscopy. The high purity, stoichiometry and spherical morphology of the gamma-Fe2O3 particles (saturation magnetization = 79 emu g(-1) and coercivity = 348 Oe) were confirmed. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</p>10achemical analysis10aDC thermal arc-plasma route10amaghemite10aMossbauer spectroscopy10aXPS1 aBanerjee, Indrani1 aKhollam, Y., B.1 aBalasubramanian, C.1 aPasricha, R.1 aBakare, P., P.1 aPatil, K., R.1 aDas, A., K.1 aBhoraskar, S., V.  uhttps://library.ncl.res.in/content/preparation-gamma-fe2o3-nanoparticles-using-dc-thermal-arc-plasma-route-their-0