01853nas a2200157   4500008004100000022001400041245011000055210006900165260007100234300001600305490000800321520120300329100001901532700001701551856012701568       2009                        eng d  a1520-610600aPhotophysical investigation into the self-organization in pyrene-based urethane methacrylate comb polymer0 aPhotophysical investigation into the selforganization in pyreneb  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP  a11887-118970 v1133 a<p>A side chain urethane methacrylate polymer with pendant pyrene units was synthesized and investigated for its self-organizing process in solution by UV-vis and fluorescence spectra and in film by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fluorescence microscopy. The polymer exhibited excimer emission centered at 476 nm, even at very dilute concentrations (10(-6) M) as a consequence of the polymer design with pendant pyrene units on every side chain. A change in aggregation pattern was observed upon increasing the concentration to 10(-4) M. New red-shifted peaks appeared in the UV-vis absorption spectra and the I(E)/I(M) ratio, and the peak I/peak III ratio showed a break around 10(-4) M, suggesting formation of stable ground state aggregates. This was further confirmed by the SEM, TEM, AFM and fluorescence microscope studies, which showed the formation of vesicles in THF and giant spherical aggregates in THF/H(2)O. The change in pattern of aggregate formation with concentration also coincided with a sudden increase in the intensity of the hydrogen bonded urethane N-H peak with concentration as recorded by solution FT-IR studies in THF.</p>1 aDeepak, V., D.1 aAsha, S., K.  uhttps://library.ncl.res.in/content/photophysical-investigation-self-organization-pyrene-based-urethane-methacrylate-comb-002120nas a2200145   4500008004100000245017500041210006900216260000800285300001800293490000700311520149000318100002801808700001701836856012101853       2011                        eng d00aPentadecyl phenol- and cardanol-functionalized fluorescent, room- temperature liquid-crystalline perylene bisimides: effect of pendant chain unsaturation on self-assembly0 aPentadecyl phenol and cardanolfunctionalized fluorescent room te  cNOV  a12646–126580 v173 a<p>A new perylene bisimide (PBI) building block based on pentadecyl phenol (PDP) or cardanol was developed, which upon esterification with 3,4,5-tridodecyloxy gallate resulted in highly emissive, room-temperature liquid-crystalline (LC) molecules. The self assembly in solution was studied in detail by NMR spectroscopy, UV/Vis absorption, and fluorescence spectroscopy. In solution both PDP- and cardanol-based PBI exhibited similar behavior. They were molecularly dissolved in chloroform (CHCl3) but formed rotationally displaced H-type aggregates that emitted at 640 nm in methylcyclohexane (MCH). Surface morphology in dropcast films were characterized using microscopic techniques such as SEM, TEM, and atomic force microscopy (AFM). The liquid-crystalline properties were studied using differential scanning calorimetry (DSC), polarized light microscopy (PLM), and variable-temperature X-ray (small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WXRD)) studies. Variable-temperature X-ray studies in the LC phase indicated strong π–π stacking interaction present in the PDP-based PBI derivative, whereas the stacking was absent in the LC phase of the cardanol-based PBI. The latter formed self-organized structures of extremely short length due to the presence of cis double bonds in the C15 alkyl side chain, whereas the saturated alkyl side chain in PDP could pack efficiently, thereby resulting in nanofibers that were several micrometers in length.</p>1 aBhavsar, Ghanashyam, A.1 aAsha, S., K.  uhttps://library.ncl.res.in/content/pentadecyl-phenol-and-cardanol-functionalized-fluorescent-room-temperature-liquid01852nas a2200157   4500008004100000022001400041245008800055210006900143260007100212300001400283490000800297520122200305100002501527700001701552856012501569       2014                        eng d  a1520-610600aPhotoresponsive smectic liquid crystalline multipods and hyperbranched azo polymers0 aPhotoresponsive smectic liquid crystalline multipods and hyperbr  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB  a1670-16840 v1183 a<p>Liquid crystalline azobenzene containing triped and tetraped monomers were designed and synthesized and further used as B-3 and B-4 type monomers to form hyperbranched polymers with tetraethylene glycol as the A(2) type comonomer. The mesophase characteristics of the multiarm-star mesogens and hyperbranched polymers were analyzed using various instrumentation techniques like differential scanning calorimetry (DSC), polarized light microscopy (PLM) and variable temperature XRD. The multipod monomers as well as hyperbranched polymers exhibited thermotropic smectic liquid crystalline characteristics with a tendency toward higher ordered smectic LC phases with increased branching. The hyperbranched polymers exhibited lamellar organization even in the as-solvent precipitated powder sample indicating higher extent of nanosegregation. Their potential application as fast switching photochromic materials was highlighted by carrying out isothermal photo-switching experiments in the LC state. Reversible isothermal smectic-isotropic phase transition could be achieved by UV irradiation in &lt;1 s in the multipod monomers, while it required &gt;2 s UV irradiation in the case of the hyperbranched polymers.</p>1 aNardele, Chinmay, G.1 aAsha, S., K.  uhttps://library.ncl.res.in/content/photoresponsive-smectic-liquid-crystalline-multipods-and-hyperbranched-azo-polymers-002444nas a2200265   4500008004100000022001400041245015200055210006900207260006700276300001400343490000700357520143400364653001901798653002901817653000901846653002101855653001801876653003301894653003201927653003001959100001501989700002802004700001702032856012902049       2016                        eng d  a0887-624X00aP4VP and oligo(phenylenevinylene)-perylenebisimide mixed donor-acceptor supramolecular comb polymer complexes with improved charge carrier mobility0 aP4VP and oligophenylenevinyleneperylenebisimide mixed donoraccep  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcAUG  a2403-24120 v543 a<p>Random donor-acceptor (D-A) supramolecular comb polymers were formed when hydroxyl functionalized donor and acceptor small molecules based on Oligo(phenylenevinylene) (named OPVCN-OH) and Perylenebisimide (named UPBI-PDP), respectively, were complexed with Poly(4-vinyl pyridine) (P4VP). A series of random D-A supramolecular comb polymers were formed by varying the ratios of UPBI-PDP and OPVCN-OH with P4VP. A 100% P4VP-donor polymer complex [P4VP(OPV1.00)] and a 100% P4VP-acceptor polymer complex [P4VP(UPBI1.00)] were also synthesized and characterized. Complex formation was confirmed by FT-IR and H-1 NMR spectroscopy. Solid state structural studies carried out using small angle X-ray scattering and wide angle X-ray diffraction experiments revealed altered packing of the D and A molecules in the complexes. Transmission electron microscopy images showed lamellar structures in the &lt;10 nm scale for the P4VP(OPV1.00), P4VP(UPBI1.00), and mixed P4VP (D-A) complexes. The effect of the nanoscopic D-A self-assembly on the bulk mobility of the materials was probed using SCLC measurements. The mixed D-A random complexes exhibited ambipolar charge transport characteristics with higher values for the average bulk hole mobility estimate. P4VP(OPV0.25+UPBI0.75) exhibited an average hole mobility in the order of 10(-2) cm(2) V-1 s(-1) and electron mobility 10(-5) cm(2) V-1 s(-1). (C) 2016 Wiley Periodicals, Inc.</p>10adonor-acceptor10aoligo(phenylenevinylene)10aP4VP10aPerylenebisimide10aSelf-assembly10astructure-property relations10asupramolecular comb polymer10asupramolecular structures1 aSaibal, B.1 aChithiravel, Sundaresan1 aAsha, S., K.  uhttps://library.ncl.res.in/content/p4vp-and-oligophenylenevinylene-perylenebisimide-mixed-donor-acceptor-supramolecular-comb02263nas a2200169   4500008004100000245015100041210006900192260000800261300001400269490000600283520159700289653002101886653001501907100002701922700001701949856012701966       2017                        eng d00api-Conjugated chromophore incorporated polystyrene nanobeads as single optical agent for three-channel fluorescent probe in bioimaging application0 apiConjugated chromophore incorporated polystyrene nanobeads as s  cAUG  a1788-17980 v33 a<p>Fluorescent polystyrene (PS) nanobeads in the size range similar to 70-120 nm incorporating perylene bisimide (PBI-PS) and/or oligo(p-phenylenevinylene) (OPV-PS) was developed by miniemulsion polymerization technique. A dye loading content (DLC) of &lt;3% was sufficient to impart high fluorescence emission capability to the PS beads. OPV-PS exhibited emission in the range 400-550 nm with peak emission at 450 nm (lambda(ex) = 350 nm; phi(FL) = 26%); PBI-PS showed emission from 520-650 nm with peak emission at 545 nm (lambda(ex) = 490 nm; phi(FL) = 9.7%) in 1x PBS buffer, whereas OPV(PBI)-PS nanobeads incorporating both the fluorophores exhibited multicolor emission capabilities (lambda(ex) from 350 to 490 nm). The nanoparticles were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) for size and zeta potential for surface charge. For bioimaging applications, the PS nanoparticles were incubated with HeLa cells. Cell viability analysis involving HeLa cells showed more than 90% cell viability confirming the biocompatibility of the PS The cellular uptake of the nanoparticles was confirmed by flow cytometry analysis and confocal laser scanning microscopy (CLSM) images. The subcellular localization of the nanoparticles in the cytoplasm could be precisely established by their simultaneous multicolor emission. The PS-based single optical agent presented here that can function as three-channel fluorescent probe to meet the requirements for multicolor bioimaging is advantageous.</p>10aBiocompatibility10abioimaging1 aMakkad, Sarabjot, Kaur1 aAsha, S., K.  uhttps://library.ncl.res.in/content/pi-conjugated-chromophore-incorporated-polystyrene-nanobeads-single-optical-agent-three01904nas a2200145   4500008004100000245012900041210006900170260000800239300001400247490000700261520132400268100002601592700001701618856012301635       2017                        eng d00aProbing cavity versus surface preference of fluorescent template molecules in molecularly imprinted polystyrene microspheres0 aProbing cavity versus surface preference of fluorescent template  cMAY  a1558-15650 v553 aFunctional polystyrene (PS) crosslinked microbeads were developed by dispersion polymerization as fluorescent molecularly imprinted polymers (MIPs) having cavities with specific recognition sites. The functional azobenzene molecule modified with pyridine was self-assembled with Pyrenebutyric acid (template molecules), and introduced during the second stage of dispersion polymerization of polystyrene. The template molecule was removed from MIP by Soxhlet using acetonitrile as solvent. Non imprinted polymer (NIP) having no template was also synthesized for comparative study. Fluorescence spectroscopy could be used as a tool to derive insight into the location of the template molecules on the MIP or NIP. The template molecules were adsorbed on the surface of the NIPs during binding studies, which was evidenced from the pyrene excimeric emission observed at 440 nm. The template binding efficiency of the NIPs were much lower compared to MIPs. Pyrene emission from MIP upon rebinding showed typical monomeric emission in the 375-395 nm range, confirming its location in isolated cavities. In rebinding studies of the template molecules, the MIPs selectively took up the template for which the cavity was designed, which demonstrated their selectivity towards template molecules. (C) 2017 Wiley Periodicals, Inc.1 aSonawane, Swapnil, L.1 aAsha, S., K.  uhttps://library.ncl.res.in/content/probing-cavity-versus-surface-preference-fluorescent-template-molecules-molecularly