01288nas a2200217 4500008004100000022001400041245008300055210006900138260010200207300001400309490000700323520047000330653001100800653002500811653002600836653002200862100002200884700002000906700003000926856011400956 2008 eng d a0011-389100aTunable surface modification of silica nanoparticles through `click' chemistry0 aTunable surface modification of silica nanoparticles through cli aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScNOV a1327-13330 v953 a

Tuning the surface functionality of silica nanoparticles through a `click' chemistry-based protocol is demonstrated. Pyrene, a fluorophore that displays excimer emission specifically at higher density/concentration is chosen for highlighting the fidelity of surface functionalization. The UV-visible absorbance of the pyrene chromophore capping the nanoparticle is used to determine the amount of pyrene units present on the surface of a silica nanoparticle.

10apyrene10asilica nanoparticles10asurface functionality10a`Click' chemistry1 aChandran, Prathap1 aHotha, Srinivas1 aPrasad, Bhagavatula L. V. uhttp://library.ncl.res.in/content/tunable-surface-modification-silica-nanoparticles-through-click-chemistry-002342nas a2200241 4500008004100000022001400041245010100055210006900156260007600225300001400301490000700315520144400322653002001766653001501786653001101801653001801812653003301830653005601863100002001919700001901939700001701958856012501975 2011 eng d a0887-624X00aCorrelation of architecture with excimer emission in 100% pyrene-labeled self-assembled polymers0 aCorrelation of architecture with excimer emission in 100 pyrenel aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcAPR a1678-16900 v493 a

Pyrene was incorporated as pendant unit to side-chain urethane methacrylate polymers having a short ethyleneoxy or a long polyethyleneoxy spacer segment. The short-spacer pyrene urethane methacrylate was also incorporated either as block or random copolymer (1:9) along with polystyrene. The excimer emission was observed to be different for different polymers with the random copolymer exhibiting the lowest efficiency. But, the total quantum yield was highest (phi = 0.58) for random copolymer due to the high emission coefficient of monomer compared to that of excimer. The polymer dynamics were compared by steady state emission and fluorescence decay in THF or THF/water (9:1) solvent mixture and films. The solid state decay profile showed decay without a rise time indicating presence of ground state aggregates. In THF/water (9:1), the decay profile at the excimer emission (500 nm) showed a rise time indicating dynamic excimers. The evolution of excimeric emission centred similar to 430 or similar to 480 nm as a function of temperature was also studied in THF/water (9:1). The I(E)/I(M) ratio for the lambda(343) nm excitation exhibited steady increase with temperature with the block copolymer PS-b-PIHP exhibiting the highest ratio and highest rate of increase; whereas, the random copolymer PS-r-PIHP had the lowest I(E)/I(M) ratios. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1678-1690, 2011

10aI(E)/I(M) ratio10aMorphology10apyrene10aSelf-assembly10astructure-property relations10atime-resolved and variable temperature fluorescence1 aKaushlendra, K.1 aDeepak, V., D.1 aAsha, S., K. uhttp://library.ncl.res.in/content/correlation-architecture-excimer-emission-100-pyrene-labeled-self-assembled-polymers-002534nas a2200217 4500008004100000022001400041245010900055210006900164260007100233300001600304490000600320520170900326653003002035653002702065653002102092653001102113653002602124100002602150700001702176856012302193 2016 eng d a1944-824400aFluorescent polystyrene microbeads as invisible security ink and optical vapor sensor for 4-nitrotoluene0 aFluorescent polystyrene microbeads as invisible security ink and a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR a10590-105990 v83 a

Color-tunable solid-state emitting polystyrene (PS) microbeads were developed by dispersion polymerization, which showed excellent fluorescent security ink characteristics along with sensitive detection of vapors of nitro aromatics like 4 nitro toluene (4-NT). The fluorophores pyrene and perylenebisimide were incorporated into the PS backbone as acrylate monomer and acrylate cross-linker, respectively. Solid state quantum yields of 94 and 20% were observed for the pyrene and perylenebisimide, respectively, in the PS/Py and PS/PBI polymers. The morphology and solid state fluorescence was measured by SEM, fluorescence microscopy, and absorbance and fluorescence spectroscopy techniques. The ethanol dispersion of the polymer could be used directly as a fluorescent security ``invisible'' ink, which became visible only under ultraviolet light. The color of the ink could be tuned depending on the amounts of the pyrene and perylenebisimide incorporated with blue and orange-green for pyrene alone or perylenebisimide alone beads respectively and various shades in between including pure white for beads incorporating both the fluorophores. More than 80% quenching of pyrene emission was observed upon exposure of the polymer in the form of powder or as spin-coated films to the vapors of 4-NT while the emission of perylenebisimide was unaffected. The limit of detection was estimated at 10(-5) moles (2.7 ppm) of 4-NT vapors. The ease of synthesis of the material along with its invisible ink characteristics and nitro aromatic vapor detection opens up new opportunities for exploring the application of these PS-based materials as optical sensors and fluorescent ink for security purposes.

10adispersion polymerization10ainvisible security ink10aPerylenebisimide10apyrene10asolid state detection1 aSonawane, Swapnil, L.1 aAsha, S., K. uhttp://library.ncl.res.in/content/fluorescent-polystyrene-microbeads-invisible-security-ink-and-optical-vapor-sensor-401604nas a2200205 4500008004100000022001400041245008900055210006900144260000800213520090400221653001001125653001801135653002401153653001101177653001201188100003301200700001501233700003001248856012001278 2019 eng d a2192-650600aBoron-conjugated pyrenes as fluorescence-based molecular probes and security markers0 aBoronconjugated pyrenes as fluorescencebased molecular probes an cJUL3 a

Boron-embedded aromatic hydrocarbons are a class of molecules known for their distinct electronic and/or optoelectronic properties and are thus suitable for many potential applications. Among those, boronic ester and acid containing molecules have been widely used for sensing and molecular recognition applications, respectively. We compared the sensing and molecular recognition properties of two boron-containing pyrene derivatives for fluoride and glucose sensing applications. The presence of four boronate ester groups enabled fluoride ion sensing at the mu M level. The boronic acid derivative is very selective towards glucose compared to other saccharides. Furthermore, we used the mechano-responsive fluorescence changes and self-assembly of these derivatives, respectively, for fluorescence-based inkless and ink (water)-based writing in invisible security labeling applications.

10aboron10acarbohydrates10amechanoluminescence10apyrene10asensors1 aWakchaure, Vivek, Chandrakan1 aDas, Tamal1 aBabu, Sukumaran, Santhosh uhttp://library.ncl.res.in/content/boron-conjugated-pyrenes-fluorescence-based-molecular-probes-and-security-markers