01889nas a2200229 4500008004100000022001400041245010200055210006900157260010000226300001400326490000700340520096800347653004401315653002601359653001301385653001301398653005301411100002501464700002601489700002201515856012201537 2010 eng d a0266-353800aPolyethersulfone-expanded graphite nanocomposites: charge transport and impedance characteristics0 aPolyethersulfoneexpanded graphite nanocomposites charge transpor aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcNOV0 a2111-21160 v703 a

Polyethersulfone (PES)-expanded graphite nanocomposites have been prepared by solution blending route after sonicating expanded graphite in dichloromethane. It has been observed that ultrasonication results in nanosheets formation leading to a low percolation threshold of 3 wt.%. At 5 wt.% filler loading the conductivity is of the order of 10(-2) S/cm. Hopping type of charge transport occurs at 3.2 wt.% expanded graphite in PES below which capacitive effects couple. The effective dielectric constant at low frequency increases with filler concentration. Impedance measurement has been carried out to evaluate interfacial capacitance which, for 3.2 wt.% expanded graphite addition in PES, increases to 110 pF from 32 pF for 1 wt.% expanded graphite in the polymer. DSC analysis shows an increment of 12 C in the T(g) of PES with 3 wt.% expanded graphite suggesting interaction between the polymer and filler. (C) 2010 Elsevier Ltd. All rights reserved.

10aDifferential scanning calorimetry (DSC)10aElectrical properties10aModeling10aPolymers10aScanning/transmission electron microscopy (STEM)1 aRamanujam, B., T. S.1 aMahale, Rajashree, Y.1 aRadhakrishnan, S. uhttps://library.ncl.res.in/content/polyethersulfone-expanded-graphite-nanocomposites-charge-transport-and-impedance-001836nas a2200181 4500008004100000022001400041245006900055210006900124260011000193300001400303490000700317520112700324100002601451700002501477700002001502700003001522856010201552 2012 eng d a1463-907600aBand edge modulated conjugated polymers for oxidation prevention0 aBand edge modulated conjugated polymers for oxidation prevention aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcFEB a4577-45830 v143 a

The impact of electron transfer (ET) from a series of band edge modulated polymers to atmospheric oxygen is examined in connection with substrate oxidation prevention. Polymers with the highest occupied molecular orbital (HOMO) energy level below and above the oxygen energy level were tested and the former showed better efficiency. Furthermore, the oxidation prevention efficiency of a polymer with lower HOMO increased by two orders of magnitude, when the pores on the film were filled with spherical molecules, [6,6]-phenyl-C61-butyric acid methyl ester. We found that the polymer surface hydrophobicity has little or no influence on oxidation prevention. It is interesting to note that a polymer with a hole mobility of 8 x 10(-10) cm(2) V-1 s(-1) showed a two-fold increase in oxidation prevention efficiency compared to a polymer with a hole mobility of 6 x 10(-5) cm(2) V-1 s(-1). Over all, from the concerted approach, we conclude that a polymer devoid of pores with the HOMO energy level below oxygen and low charge carrier mobility is a suitable candidate for prevention of substrate oxidation/corrosion.

1 aMahale, Rajashree, Y.1 aArulkashmir, Arulraj1 aDutta, Kingshuk1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/band-edge-modulated-conjugated-polymers-oxidation-prevention-001612nas a2200169 4500008004100000245012300041210006900164260000800233300001600241490000700257520095300264100002001217700002601237700002501263700003001288856012401318 2012 eng d00aReversible assembly and disassembly of micelles by a polymer that switches betweenhydrophilic and hydrophobic wettings0 aReversible assembly and disassembly of micelles by a polymer tha cJUN a10097-101040 v283 aSupramolecular complexes involving nanoscopic amphiphilic assemblies (AAs) and polyelectrolytes have been used to prepare a variety of materials, wherein the dynamic AAs retain the structural features, but the polyelectrolytes undergo conformational changes. Here we show that a charge bearing rigid conjugated polymer can alter the structural features and disassemble AAs. We also demonstrate reversible assembly and disassembly of AAs by controlling the number of charges on the rigid polymer. During the disassembly, the guest molecules sequestered in the AAs are released. The rate of release has been modulated by changing the morphology of the charge bearing polymer. Concomitant to the AAs disassembly, the polymer surface becomes hydrophobic due to the binding of the amphiphiles on the charges of the polymer backbone. By controlling the charges on the polymer, the surface wettability was varied gradually from hydrophilic to hydrophobic.1 aDutta, Kingshuk1 aMahale, Rajashree, Y.1 aArulkashmir, Arulraj1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/reversible-assembly-and-disassembly-micelles-polymer-switches-betweenhydrophilic-and02097nas a2200181 4500008004100000245010100041210006900142260000800211300001400219490000600233520141200239100002501651700002601676700002901702700002201731700003001753856013201783 2012 eng d00aSupramolecular interaction facilitated small molecule films for organic field effect transistors0 aSupramolecular interaction facilitated small molecule films for  cAPR a1641-16460 v33 aMetalloporphyrins and metal free porphyrins have been explored as active materials in field effect transistors. Amorphous forms of these porphyrins are preferred over their crystalline analogue due to the ease of solution processability. To achieve solution processability, a metalloporphyrin was anchored on a vinyl polymer by taking advantage of the supramolecular interaction between the metal and the pyridine moiety of the polymer. Non covalent bonding was preferred because it provides an opportunity to better manipulate the polymer's properties compared to its covalent bonding analogue. The binding between the porphyrin and the polymer was optimised in solution and the supramolecular complex was spun on various substrates to form thin films. The porphyrin was found to be uniformly distributed throughout the polymer films contrary to the existing approaches, wherein small molecule phase segregates in the polymer film. Field effect transistors were fabricated using the porphyrin-polymer complex and the device parameters were measured at atmospheric condition. The devices annealed at 80 degrees C showed hole carrier mobility of 2.0 x 10(-4) cm(2) V-1 s(-1) with charge trapping at the dielectric semiconductor interface. Furthermore, the high carrier mobility observed at low temperature annealing makes this supramolecular complex an attractive candidate to explore in flexible substrates.1 aArulkashmir, Arulraj1 aMahale, Rajashree, Y.1 aDharmapurikar, Satej, S.1 aJangid, Manoj, K.1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/supramolecular-interaction-facilitated-small-molecule-films-organic-field-effect-transistors01343nas a2200157 4500008004100000245011200041210006900153260000800222300001200230490000800242520072900250100002600979700002601005700002401031856013001055 2016 eng d00aEffect of heterocycles on field-effect transistor performances of donor-acceptor-donor type small molecules0 aEffect of heterocycles on fieldeffect transistor performances of cSEP a107-1130 v6613 aTwo D-A-D small molecules comprising triphenylamine and diketopyrrolopyrrole were synthesized having either furan or thiophene connected to the fused lactam ring. In this design, furan/thiophene diketopyrrolopyrrole acts as an acceptor and triphenylamine acts as a donor. Propeller shaped triphenylamine has its effect on packing, processability and plays a vital role in determining the pi-pi molecular orbital stacking in such compounds and thus the mobility of charge carriers. With TDPPT and FDPPT, maximum hole carrier mobility obtained is 2.88 x 10(-3) cm(2) V-1 s(-1) and 1.60 x 10(-3) cm(2) V-1 s(-1), respectively using bottom gate bottom contact field-effect transistor. (C) 2016 Elsevier B.V. All rights reserved.1 aChini, Mrinmoy, Kumar1 aMahale, Rajashree, Y.1 aChatterjee, Shyambo uhttps://library.ncl.res.in/content/effect-heterocycles-field-effect-transistor-performances-donor-acceptor-donor-type-small-001448nas a2200169 4500008004100000245011300041210006900154260000800223300001200231490000800243520079400251100002601045700002901071700002601100700002301126856012901149 2017 eng d00aInfluence of thermocleavable functionality on organic field-effect transistor performance of small molecules0 aInfluence of thermocleavable functionality on organic fieldeffec cJUN a139-1450 v6783 aDiketopyrrolopyrrole based donor-acceptor-donor conjugated small molecules using ethylene dioxythiophene as a donor was synthesized. Electron deficient diketopyrrolopyrrole unit was substituted with thermocleavable (tert-butyl acetate) side chains. The thermal treatment of the molecules at 160 degrees C eliminated the tert-butyl ester group results in the formation of corresponding acid. Optical and theoretical studies revealed that the molecules adopted a change in molecular arrangement after thermolysis. The conjugated small molecules possessed p-channel charge transport characteristics in organic field effect transistors. The charge carrier mobility was increased after thermolysis of tert-butyl ester group to 5.07 x 10(-5) cm(2)/Vs. (C) 2017 Elsevier B.V. All rights reserved.1 aMahale, Rajashree, Y.1 aDharmapurikar, Satej, S.1 aChini, Mrinmoy, Kumar1 aVenugopalan, Vijay uhttps://library.ncl.res.in/content/influence-thermocleavable-functionality-organic-field-effect-transistor-performance-small02034nas a2200289 4500008004100000022001400041245010900055210006900164260000800233490000800241520101300249653001001262653008901272653002401361653002101385653001301406653001401419653001901433653001601452653001601468653002601484100002901510700002501539700002601564700002601590856012801616 2017 eng d a0021-899500aSynthesis of amphiphilic isoindigo co-polymers for organic field effect transistors: A comparative study0 aSynthesis of amphiphilic isoindigo copolymers for organic field  cNOV0 v1343 a

In this work, the amphiphilic isoindigo (am-iInd) based conjugated polymers namely poly(am-iInd-DT) and poly(am-iInd-TT) and their regular counterpart poly(reg-iInd-DT) and poly(reg-iInd-TT) were synthesized to compare their opto-electronic and charge transport properties. They were used to fabricate organic field effect transistors. Charge transport properties in conjugated polymers depend upon intermolecular interaction which is strongly affected by the nature of side chains. The amphiphilic nature of the conjugated polymers has little impact on the charge transport properties. The charge carrier mobility of amphiphilic conjugated polymers was comparable with the regular polymers except poly(reg-iInd-DT) which can be correlated by X-ray diffraction and thin film morphology. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45461.

10aAlkyl10aApplications; Conducting polymers; Copolymers; Optical and Photovoltaic applications10aconjugated polymers10aHigh-performance10amobility10aPackaging10aSemicondoctors10aSide-chains10aSolar-cells10aThin-film Transformer1 aDharmapurikar, Satej, S.1 aArulkashmir, Arulraj1 aMahale, Rajashree, Y.1 aChini, Mrinmoy, Kumar uhttps://library.ncl.res.in/content/synthesis-amphiphilic-isoindigo-co-polymers-organic-field-effect-transistors-comparative01364nas a2200157 4500008004100000245011900041210006900160260000800229300001000237490000800247520074200255100002600997700002901023700002601052856012801078 2018 eng d00aChemical oxidative and solid state synthesis of low molecular weight polymers for organic field effect transistors0 aChemical oxidative and solid state synthesis of low molecular we cMAR a48-540 v6963 aSolution processability of the precursor molecules is a major issue owing to their limited solubility for the synthesis of conjugated polymers. Therefore, we favour the solvent free solid state chemical oxidative polymerization route for the synthesis of diketopyrrolopyrrole (DPP) based donor-acceptor (D-A) type conjugated polymers. D-A type polymer Poly(S-OD-EDOT) which contains DPP coupled with EDOT donor units is synthesized via solid state polymerization method. The polymer is employed as an active layer for organic field-effect transistors to measure charge transport properties. The Polymer shows good hole mobility 3.1 x 10(-2) cm(2) V-1 s(-1), with a on/off ratio of 1.1 x 10(3). (C) 2018 Elsevier B.V. All rights reserved.1 aMahale, Rajashree, Y.1 aDharmapurikar, Satej, S.1 aChini, Mrinmoy, Kumar uhttps://library.ncl.res.in/content/chemical-oxidative-and-solid-state-synthesis-low-molecular-weight-polymers-organic-field02131nas a2200253 4500008004100000245010800041210006900149260000800218300001400226490000600240520124600246653001901492653002501511653002601536653002301562653002301585653002701608100002301635700002201658700002601680700002101706700003001727856012001757 2022 eng d00aInstabilities as the origin of large-area self-assembled and aligned organic semiconductor nanocrystals0 aInstabilities as the origin of largearea selfassembled and align cAPR a1815-18220 v43 a

Aligned nanocrystals of organic semiconductors (OSCs) are highly desirable for electronic devices and biomedical and photonic applications. Solution-based wet processing routes have the potential to produce aligned nanocrystals over large areas in small time frames. Herein, we demonstrate that by optimizing the hydrodynamic evaporative processes, controlled long-range crystalline assemblies of OSCs can be achieved (longest nanocrystal similar to 3 mm) purely through physical processes: namely, from fingering instabilities. Self-assembly is achieved here without strong noncovalent interactions such as hydrogen-bonding interactions. Experimentally our approach involves just placing a drop of a solution on an inclined substrate. Nanocrystals with widths of 300-800 nm and lengths of millimeters (length/width aspect ratios >10(5)) are formed in less than 2-8 s. A hydrazine chemiresistive sensor based on the aligned crystalline patterns show unprecedented responsivity (similar to 10(-6)), 2 orders greater than those of stick-slip patterns. Finally, experimental parameters that need optimization to achieve nanocrystal patterns are investigated in detail and pointers to fabricate such OSC nanocrystals are provided.

10aaligned fibers10adiketopyrrolopyrrole10afingering instability10ananocrystal arrays10anaphthalenediimide10aorganic semiconductors1 aVenugopalan, Vijay1 aJain, Bhanprakash1 aMahale, Rajashree, Y.1 aSubramani, Kumar1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/instabilities-origin-large-area-self-assembled-and-aligned-organic-semiconductor