Sudha J DEVAKI
NIIST, CSIR-NIIST,Trivandrum, Faculty Member
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Energy storage devices accomplished with efficient LAPONITE® liquid crystalline gel electrolytes.
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Nanostructured polyaniline-polytitanate-clay composite (PPTC) was prepared by the polymerization of anilinium hydrochloride in a dispersion of polytitanate functionalized clay at room temperature. Modified clay-polytitanate adsorbs... more
Nanostructured polyaniline-polytitanate-clay composite (PPTC) was prepared by the polymerization of anilinium hydrochloride in a dispersion of polytitanate functionalized clay at room temperature. Modified clay-polytitanate adsorbs anilinium ions by ion-dipole interactions and will act as a template. During polymerisation, polyaniline forms linkages between these disorganized titanate modified clay layers and may co-structure with the self-assembled polyaniline layers. They then roll up to form three dimensionally ordered nanotubes by a self-assembly process which was confirmed by morphological analysis, EDS and XRD. The photocatalytic efficiency of this PPTC was demonstrated by performing the photodegradation studies of methylene blue and methyl orange at room temperature under natural light irradiation. Studies revealed that this novel PPTC nanocomposite can be used as a prospective candidate for the disposal of pollutants present in the environment.
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Vitamin C is a water-soluble compound found in living organisms. It is an essential nutrient for various metabolism in our body and also serves as a reagent for the preparation of many materials in the pharmaceutical and food industry. In... more
Vitamin C is a water-soluble compound found in living organisms. It is an essential nutrient for various metabolism in our body and also serves as a reagent for the preparation of many materials in the pharmaceutical and food industry. In this perspective, this chapter can develop interest and curiosity among all practicing scientists and technologists by expounding the details of its sources, chemistry, multifunctional properties and applications.
The structure-directing effect of two amphiphilic dopants on the nucleation and growth mechanism during the formation of micro/ nanostructured polyaniline (PANI) and polyaniline-clay nanocomposites (PANICNs) is described. PANIs and... more
The structure-directing effect of two amphiphilic dopants on the nucleation and growth mechanism during the formation of micro/ nanostructured polyaniline (PANI) and polyaniline-clay nanocomposites (PANICNs) is described. PANIs and PANICNs were prepared by in-situ intercalative emulsion polymerization of aniline using the amphiphilic dopants, 3-pentadecyl phenyl phosphoric acid (3-PDPPA) and 3-pentadecyl phenol-4-sulphonic acid (3-PDPSA), derived from cashew nut shell liquid, a renewable resource. These molecules act as intercalating agents, dopants and also as structure-directing agents. X- ray diffraction (XRD) and scanning electron microscopic (SEM) studies revealed the formation of lamellar/fibrillar - network in PANI- PDPPA and cylinder/rod morphology in PANI-PDPSA. Experimental data reveal that fibrillar morphology arises from the heterogeneous nucleation followed by an indefinite growth mechanism. On the other hand rod-like structures are formed from the self-assembled rod-like micelle guided polymerization through homonucleation followed by an anisotropic growth mechanism. Electrical conductivity measurement revealed lower conductivities for PANICNs than that of PANIs.
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This paper demonstrates a facile strategy for the development of nanosilver decorated polyaniline coated (PAg) paper-based electrodes for the fabrication of solid-state symmetrical supercapacitors.
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Development of silver nanoparticles entrapped hydrogels for antimicrobial applications.
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Self-assembled polyaniline nanowires stippled graphene nanocomposites (PGPCs) were prepared by in situ polymerisation of aniline in the presence of 3-pentadecylphenyl phosphate (3-PDPP) modified graphene sheets.
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Polyethylene (PE), a general-purpose thermoplastic, finds wide-ranging applications in many areas such as packaging films, electrical insulations, housewares, pipes and tubings, etc. [I]. For certain applications such as the insulation... more
Polyethylene (PE), a general-purpose thermoplastic, finds wide-ranging applications in many areas such as packaging films, electrical insulations, housewares, pipes and tubings, etc. [I]. For certain applications such as the insulation and sheathing of power cables used for off-shore mining, flame retardancy is an essential service requirement. Some of the other applications for flame-proofed polyolefins include components for TV sets and
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In recent times, cyanate ester-epoxy blends together with kapton have become an attractive candidate as an insulation system for fusion grade magnet winding packs such as International Thermonuclear Experimental Reactor (ITER) and DEMO... more
In recent times, cyanate ester-epoxy blends together with kapton have become an attractive candidate as an insulation system for fusion grade magnet winding packs such as International Thermonuclear Experimental Reactor (ITER) and DEMO reactors.1, 2 Fusion relevant magnets winding ...
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ABSTRACT: Novel self-assembled nano/microstructured conducting PANICN was prepared by in situ intercalative emulsion polymerization of aniline in aqueous dispersion of clay using bifunctional amphiphilic dopant, 3-pentadecyl... more
ABSTRACT: Novel self-assembled nano/microstructured conducting PANICN was prepared
by in situ intercalative emulsion polymerization of aniline in aqueous dispersion
of clay using bifunctional amphiphilic dopant, 3-pentadecyl phenol-4-sulphonic acid
(PDPSA) derivable from renewable resource. X-ray diffraction and scanning electron
microscopy (SEM) studies revealed the formation of monolayer of protonated PANI
intercalated nanoclays with template polymerized self-assembled micro/nanostructured
protonated PANI. Nano/micro structured PANIs were formed by the supra molecular
self-assembling of the inter-chain hydrogen bonding, inter-plane phenyl stacking
and electrostatic layer by layer self-assembling (ELBS) between polarized alkyl
chains present dopant anions and were manifested using fourier transform infra red
spectroscopy and differential scanning calorimetry. On the basis of the results, structure-
directing effect of ‘anilinium salt micelle’ was schematically illustrated in this article.
VVC 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2664–2673, 2007
Keywords: clay; conducting polymer; intercalating agent; micelles; morphology;
nanocomposite; renewable resource; self assembling
by in situ intercalative emulsion polymerization of aniline in aqueous dispersion
of clay using bifunctional amphiphilic dopant, 3-pentadecyl phenol-4-sulphonic acid
(PDPSA) derivable from renewable resource. X-ray diffraction and scanning electron
microscopy (SEM) studies revealed the formation of monolayer of protonated PANI
intercalated nanoclays with template polymerized self-assembled micro/nanostructured
protonated PANI. Nano/micro structured PANIs were formed by the supra molecular
self-assembling of the inter-chain hydrogen bonding, inter-plane phenyl stacking
and electrostatic layer by layer self-assembling (ELBS) between polarized alkyl
chains present dopant anions and were manifested using fourier transform infra red
spectroscopy and differential scanning calorimetry. On the basis of the results, structure-
directing effect of ‘anilinium salt micelle’ was schematically illustrated in this article.
VVC 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2664–2673, 2007
Keywords: clay; conducting polymer; intercalating agent; micelles; morphology;
nanocomposite; renewable resource; self assembling
ABSTRACT: Fifteen highly regular hydrogen-bonded, novel thermotropic, aromatic-aliphatic poly(ester–amide)s (PEAs) were synthesized from aliphatic amido diols by melt polycondensation with dimethyl terephthalate and solution... more
ABSTRACT: Fifteen highly regular hydrogen-bonded, novel thermotropic, aromatic-aliphatic
poly(ester–amide)s (PEAs) were synthesized from aliphatic amido diols by melt
polycondensation with dimethyl terephthalate and solution polycondensation with
terephthaloyl chloride. Intermolecular hydrogen bonds more or less perpendicular to
the main-chain direction induce the formation and stabilization of liquid crystalline
property for these PEAs. The structure of these polymers, even in the mesomorphic
phase is dominated by hydrogen bonds between the amide–amide and amide–ester
groups in adjacent chains. Aliphatic amido diols were synthesized by the aminolysis of
g-butyrolactone, d-valerolactone and «-caprolactone with aliphatic diamines containing
a number of methylene groups from two to six in isopropanol medium at room temperature.
Effects of polarity of the solvent on solution polymerization and effect of catalyst
on trans esterification were studied. These polymers were characterized by elemental
analysis, FTIR, 1H NMR, 13C NMR, solubility studies, inherent viscosity, DSC, X-ray
diffraction, polarized light microscopy, and TGA. All the melt/solution polycondensed
PEAs showed multiple-phase transitions on heating with second transitions identified
as nematic/smectic/spherullitic texture. The mesomorphic properties were studied as a
function of their chemical structure by changing alternatively m or n. Odd-even effect
on mesophase transition temperature, isotropization temperature, and crystallinity
were studied. The effect of molecular weight and polydispersity on mesophase/isotropization
temperature and thermal stability were investigated. It was observed that
there exists a competition for crystallinity and liquid crystallinity in these PEAs. © 2000
John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2469–2486, 2000
Keywords: thermotropic; amido diol; poly(ester–amide); liquid crystalline, hydrogen
poly(ester–amide)s (PEAs) were synthesized from aliphatic amido diols by melt
polycondensation with dimethyl terephthalate and solution polycondensation with
terephthaloyl chloride. Intermolecular hydrogen bonds more or less perpendicular to
the main-chain direction induce the formation and stabilization of liquid crystalline
property for these PEAs. The structure of these polymers, even in the mesomorphic
phase is dominated by hydrogen bonds between the amide–amide and amide–ester
groups in adjacent chains. Aliphatic amido diols were synthesized by the aminolysis of
g-butyrolactone, d-valerolactone and «-caprolactone with aliphatic diamines containing
a number of methylene groups from two to six in isopropanol medium at room temperature.
Effects of polarity of the solvent on solution polymerization and effect of catalyst
on trans esterification were studied. These polymers were characterized by elemental
analysis, FTIR, 1H NMR, 13C NMR, solubility studies, inherent viscosity, DSC, X-ray
diffraction, polarized light microscopy, and TGA. All the melt/solution polycondensed
PEAs showed multiple-phase transitions on heating with second transitions identified
as nematic/smectic/spherullitic texture. The mesomorphic properties were studied as a
function of their chemical structure by changing alternatively m or n. Odd-even effect
on mesophase transition temperature, isotropization temperature, and crystallinity
were studied. The effect of molecular weight and polydispersity on mesophase/isotropization
temperature and thermal stability were investigated. It was observed that
there exists a competition for crystallinity and liquid crystallinity in these PEAs. © 2000
John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2469–2486, 2000
Keywords: thermotropic; amido diol; poly(ester–amide); liquid crystalline, hydrogen
ABSTRACT: Herein, we report the preparation of robust polyacrylic acid hydrogel using rod-like amidodiol as physical crosslinker. Polyacrylic acid–amidodiol hydrogels were characterized for its chemical structure, rheology, swelling,... more
ABSTRACT: Herein, we report the preparation of robust polyacrylic acid hydrogel using rod-like amidodiol as physical crosslinker.
Polyacrylic acid–amidodiol hydrogels were characterized for its chemical structure, rheology, swelling, diffusion, and adsorption properties.
Kinetics and mechanism of adsorption were investigated by UV–visible spectroscopy using dyes such as rhodamine 6G and
methylene blue as adsorbate. Results suggested pseudo second-order kinetics of multilayer adsorption and hydrogel could retain its
shape even after swelling. Effect of amidodiol on the adsorption of dyes was investigated. Extent of interaction between adsorbate–
adsorbate and adsorbent–adsorbate was studied using Gile’s model. The generated results may provide a low cost simple technology
for developing robust polymeric hydrogel adsorbent. The adsorption characteristics results can be exploited for setting up pilot plant
adsorbent for the removal of such organic toxic materials. Finally, we have demonstrated its application for the removal of dyes from
waste water collected from textile and paper industries. VC 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40908.
Polyacrylic acid–amidodiol hydrogels were characterized for its chemical structure, rheology, swelling, diffusion, and adsorption properties.
Kinetics and mechanism of adsorption were investigated by UV–visible spectroscopy using dyes such as rhodamine 6G and
methylene blue as adsorbate. Results suggested pseudo second-order kinetics of multilayer adsorption and hydrogel could retain its
shape even after swelling. Effect of amidodiol on the adsorption of dyes was investigated. Extent of interaction between adsorbate–
adsorbate and adsorbent–adsorbate was studied using Gile’s model. The generated results may provide a low cost simple technology
for developing robust polymeric hydrogel adsorbent. The adsorption characteristics results can be exploited for setting up pilot plant
adsorbent for the removal of such organic toxic materials. Finally, we have demonstrated its application for the removal of dyes from
waste water collected from textile and paper industries. VC 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40908.
ABSTRACT: This article demonstrates the design and fabrication of an electrochemical sensor based on a platinum electrode for ascorbic acid (AA) modified by an electromagnetic polyaniline–Keggin iron–clay (PPICS) composite. The... more
ABSTRACT: This article demonstrates the design and fabrication of an electrochemical sensor based on a platinum electrode for ascorbic
acid (AA) modified by an electromagnetic polyaniline–Keggin iron–clay (PPICS) composite. The polyaniline–polyhydroxy iron–
clay composite was prepared by the polymerization of [Anilinium]1[PDPSA]2 in the presence of Keggin iron intercalated clay and
was characterized for its particle size, morphology, electrical conductivity, and saturation magnetization. The oxidation potential of
AA was observed at 10.4 V on the bare electrode and shifted to a negative potential of 20.32 V on the modified electrode. Common
possible interferences of the sample matrices were tested, and the results reveal that the PPICS-modified electrode exhibited a high
selectivity and sensitivity toward AA. This unique low-cost and user-friendly sensor was validated for the nanomolar detection of AA
acid (AA) modified by an electromagnetic polyaniline–Keggin iron–clay (PPICS) composite. The polyaniline–polyhydroxy iron–
clay composite was prepared by the polymerization of [Anilinium]1[PDPSA]2 in the presence of Keggin iron intercalated clay and
was characterized for its particle size, morphology, electrical conductivity, and saturation magnetization. The oxidation potential of
AA was observed at 10.4 V on the bare electrode and shifted to a negative potential of 20.32 V on the modified electrode. Common
possible interferences of the sample matrices were tested, and the results reveal that the PPICS-modified electrode exhibited a high
selectivity and sensitivity toward AA. This unique low-cost and user-friendly sensor was validated for the nanomolar detection of AA
Twelve hydrogen bonded aromatic–aliphatic poly(ester amide)s differing in the structures of their aromatic moieties (isophthalic, terephthalic, 2,6-naphthyl and 4,40-biphenyl moieties of the dicarboxylic acid and phenylene and xylylene... more
Twelve hydrogen bonded aromatic–aliphatic poly(ester amide)s differing in the structures of their aromatic moieties (isophthalic,
terephthalic, 2,6-naphthyl and 4,40-biphenyl moieties of the dicarboxylic acid and phenylene and xylylene moieties of the amido diol part)
were prepared by the polycondensation of amido diols with acid chlorides of isophthalic acid, terephthalic acid, 2,6-naphthalic dicarboxylic
acid and 4,40-biphenyl dicarboxylic acid, respectively. The amido diols were prepared by the aminolysis of g-butyrolactone with
hexamethylene diamine, para phenylene diamine and para xylylenene diamine, respectively. The PEAs were characterised for elemental
analysis, FTIR, 13C NMR, TGA, DSC, POM, isothermal viscosity measurements and WAXD. Here we are presenting the effect of aromatic
moieties on the thermotropic and lyotropic (amphotropic) properties of PEAs. These PEAs are essentially constituted of six types of
structural entities, i.e. isophthalic, terephthalic, 2,6-naphthalic and 4,40-biphenyl moieties containing dicarboxylic acid and the aliphatic,
aromatic (phenylene and xylylene moieties) of the di-amide linkage of the amido diol part. The structure of the polymers even in the
mesophase is dominated by hydrogen bond interaction between the adjacent chains and also inter plane mesogenic interaction between the
rigid aromatic group. It was observed morphologically that the formation of different forms of nematic/smectic/columnar/spherullitic phases
in PEAs are due to the delicate balance of self assembling through hetero intermolecular hydrogen bonded amide–amide and amide–ester net
works and also inter-plane mesogenic interactions.
terephthalic, 2,6-naphthyl and 4,40-biphenyl moieties of the dicarboxylic acid and phenylene and xylylene moieties of the amido diol part)
were prepared by the polycondensation of amido diols with acid chlorides of isophthalic acid, terephthalic acid, 2,6-naphthalic dicarboxylic
acid and 4,40-biphenyl dicarboxylic acid, respectively. The amido diols were prepared by the aminolysis of g-butyrolactone with
hexamethylene diamine, para phenylene diamine and para xylylenene diamine, respectively. The PEAs were characterised for elemental
analysis, FTIR, 13C NMR, TGA, DSC, POM, isothermal viscosity measurements and WAXD. Here we are presenting the effect of aromatic
moieties on the thermotropic and lyotropic (amphotropic) properties of PEAs. These PEAs are essentially constituted of six types of
structural entities, i.e. isophthalic, terephthalic, 2,6-naphthalic and 4,40-biphenyl moieties containing dicarboxylic acid and the aliphatic,
aromatic (phenylene and xylylene moieties) of the di-amide linkage of the amido diol part. The structure of the polymers even in the
mesophase is dominated by hydrogen bond interaction between the adjacent chains and also inter plane mesogenic interaction between the
rigid aromatic group. It was observed morphologically that the formation of different forms of nematic/smectic/columnar/spherullitic phases
in PEAs are due to the delicate balance of self assembling through hetero intermolecular hydrogen bonded amide–amide and amide–ester net
works and also inter-plane mesogenic interactions.
ABSTRACT: Hydrogen-bonded aromatic–aliphatic polyester–amides (PEAs) were prepared by solution/melt polycondensation of aromatic–aliphatic amidodiols 1,4-bis(4-hydroxybutyramide) benzene (BHBB), 1,4-bis(5-hydroxy pentamide)benzene,... more
ABSTRACT: Hydrogen-bonded aromatic–aliphatic polyester–amides (PEAs) were prepared
by solution/melt polycondensation of aromatic–aliphatic amidodiols 1,4-bis(4-hydroxybutyramide)
benzene (BHBB), 1,4-bis(5-hydroxy pentamide)benzene, 1,4-bis(6-hydroxyhexamide)
benzene, 1,4-bis(4-hydroxybutyramidexylene), 1,4-bis(5-hydroxypentamidexylene,
1,4-bis(4-hydroxybutyramide)benzene, and 1,4-bis(6-hydroxyhexamidexylene) with
terephthaloyl chloride/dimethyl terephthalate. Aromatic–aliphatic amido diols were prepared
by the aminolysis of -butyrolactone, -valerolactone, and -caprolactone with aromatic
diamines such as paraphenylene diamine and paraxylene diamine. The monomers
and polymers were characterized by chemical analysis (hydroxyl value and elemental
analysis), Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR. The thermaland
phase-transition behaviors of the polymers were investigated by differential scanning
calorimetry in combination with hot-stage optical microscopy. Crystallinity of polymers
was examined with wide-angle X-ray diffraction. The polymers exhibited liquid crystallinity
with layered structures formed by self-organization of the hetero intermolecular hydrogen-
bonded networks indicating smectic phases except for PEAs prepared from BHBB. The
hydrogen atom of the phenyl-substituent group forces the neighboring carbonyl groups out
of plane of the rings preventing formation of layered structures in the case of BHBB. The
PEAs retained intermolecular hydrogen bonding even in the mesomorphic state, and
variations in the hydrogen-bonded lamellae/micelles might be responsible for the variations
from one smectic to another texture. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A:
Polym Chem 41: 335–346, 2003
by solution/melt polycondensation of aromatic–aliphatic amidodiols 1,4-bis(4-hydroxybutyramide)
benzene (BHBB), 1,4-bis(5-hydroxy pentamide)benzene, 1,4-bis(6-hydroxyhexamide)
benzene, 1,4-bis(4-hydroxybutyramidexylene), 1,4-bis(5-hydroxypentamidexylene,
1,4-bis(4-hydroxybutyramide)benzene, and 1,4-bis(6-hydroxyhexamidexylene) with
terephthaloyl chloride/dimethyl terephthalate. Aromatic–aliphatic amido diols were prepared
by the aminolysis of -butyrolactone, -valerolactone, and -caprolactone with aromatic
diamines such as paraphenylene diamine and paraxylene diamine. The monomers
and polymers were characterized by chemical analysis (hydroxyl value and elemental
analysis), Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR. The thermaland
phase-transition behaviors of the polymers were investigated by differential scanning
calorimetry in combination with hot-stage optical microscopy. Crystallinity of polymers
was examined with wide-angle X-ray diffraction. The polymers exhibited liquid crystallinity
with layered structures formed by self-organization of the hetero intermolecular hydrogen-
bonded networks indicating smectic phases except for PEAs prepared from BHBB. The
hydrogen atom of the phenyl-substituent group forces the neighboring carbonyl groups out
of plane of the rings preventing formation of layered structures in the case of BHBB. The
PEAs retained intermolecular hydrogen bonding even in the mesomorphic state, and
variations in the hydrogen-bonded lamellae/micelles might be responsible for the variations
from one smectic to another texture. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A:
Polym Chem 41: 335–346, 2003
Electricallyconductinghydrogelnanocompositebasedonsilvernanoparticles–polyacrylicacidhasbeen preparedbyinsitupolymerizationofacrylicacidandreductionofsilverionsusingmethylolureaasagelling cum... more
Electricallyconductinghydrogelnanocompositebasedonsilvernanoparticles–polyacrylicacidhasbeen
preparedbyinsitupolymerizationofacrylicacidandreductionofsilverionsusingmethylolureaasagelling
cum reducingagentatroomtemperature.Effectofsilverionconcentrationontheopticalproperties,
morphology andconductivitywasstudied.Swellingdependentelectricalconductivityresultssuggestedthat
these hydrogelscanbeconsideredasapromisingcandidateinmanyadvancedtechnologicalapplications
such asnanoelectronicdevices,electric fieldcontrolledartificial musclesandsoforth
preparedbyinsitupolymerizationofacrylicacidandreductionofsilverionsusingmethylolureaasagelling
cum reducingagentatroomtemperature.Effectofsilverionconcentrationontheopticalproperties,
morphology andconductivitywasstudied.Swellingdependentelectricalconductivityresultssuggestedthat
these hydrogelscanbeconsideredasapromisingcandidateinmanyadvancedtechnologicalapplications
such asnanoelectronicdevices,electric fieldcontrolledartificial musclesandsoforth
Abstract Thermosetting blend system of co-cured cyanate ester with epoxy resin is receiving importance for high technological applications because of its wide range of thermo-mechanical, rheological, and electrical properties. However,... more
Abstract Thermosetting blend system of co-cured cyanate
ester with epoxy resin is receiving importance for high
technological applications because of its wide range of
thermo-mechanical, rheological, and electrical properties.
However, processing of these system warrant proper
knowledge of the rheological behavior of the blend during
the curing process. This article discusses the rheological
behavior of the blend systems with respect to the pot life,
gel time, gelation temperature and also evaluated fitting
parameters for the prediction of gelation time and viscosity
during the entire curing process from the isothermal rheological
measurements
ester with epoxy resin is receiving importance for high
technological applications because of its wide range of
thermo-mechanical, rheological, and electrical properties.
However, processing of these system warrant proper
knowledge of the rheological behavior of the blend during
the curing process. This article discusses the rheological
behavior of the blend systems with respect to the pot life,
gel time, gelation temperature and also evaluated fitting
parameters for the prediction of gelation time and viscosity
during the entire curing process from the isothermal rheological
measurements
ABSTRACT: This paper demonstrates a facile bioanchoring strategy for controlling the crystal growth process of ZnO crystals during calcination to form hierarchical multiple structures. Crystalline phase and morphology of ZnO was... more
ABSTRACT: This paper demonstrates a facile bioanchoring strategy for
controlling the crystal growth process of ZnO crystals during calcination to
form hierarchical multiple structures. Crystalline phase and morphology of
ZnO was investigated using X-ray diffraction, scanning electron microscopy,
transmission electron microscopy, and atomic force microscopy. Results
revealed the evolution of ZnO nanocrystallites from nanosize to hierarchical
self-assembly of polydispersed microstructures of bars/sheets/spheres/hollow
spheres in wurzite hexagonal phase. ZnO exhibited photoluminescence
attributed to the presence of various defects which was further supported by
Raman spectroscopy and energy-dispersive X-ray spectroscopy. On the basis
of the various experimental results, a plausible growth mechanism for the
formation of multiple structures of ZnO crystals is proposed. Further
demonstrated is the application of the polydispersed submicrometer sized
ZnO crystals as photoanode in dye sensitized solar cells for improving the power conversion efficiency (∼5.3%) through high dye
loading and enhanced light absorption edge via inherent light reflection mechanism.
controlling the crystal growth process of ZnO crystals during calcination to
form hierarchical multiple structures. Crystalline phase and morphology of
ZnO was investigated using X-ray diffraction, scanning electron microscopy,
transmission electron microscopy, and atomic force microscopy. Results
revealed the evolution of ZnO nanocrystallites from nanosize to hierarchical
self-assembly of polydispersed microstructures of bars/sheets/spheres/hollow
spheres in wurzite hexagonal phase. ZnO exhibited photoluminescence
attributed to the presence of various defects which was further supported by
Raman spectroscopy and energy-dispersive X-ray spectroscopy. On the basis
of the various experimental results, a plausible growth mechanism for the
formation of multiple structures of ZnO crystals is proposed. Further
demonstrated is the application of the polydispersed submicrometer sized
ZnO crystals as photoanode in dye sensitized solar cells for improving the power conversion efficiency (∼5.3%) through high dye
loading and enhanced light absorption edge via inherent light reflection mechanism.
In this work, we demonstrate an inimitable liquid crystalline template strategy for the preparation of water dispersible electrically conducting poly(3,4-ethylenedioxythiophene) nanospindles (PEDOTSs). PEDOTSs were formed during the... more
In this work, we demonstrate an inimitable liquid crystalline template strategy for the preparation of water
dispersible electrically conducting poly(3,4-ethylenedioxythiophene) nanospindles (PEDOTSs). PEDOTSs
were formed during the polymerization of the spindle shaped liquid crystalline phase of “EDOT–PDPSA”
which was formed by the specific interactions of 3,4-ethylenedioxythiophene (EDOT) with 3-pentadecyl
phenol-4-sulphonic acid (PDPSA). Liquid crystalline phases were characterized by Polarized Light
Microscopic (PLM) analyses, rheology and XRD. Morphology and solid state ordering of conducting
nanospindles were characterized by SEM, TEM and XRD. PEDOTSs exhibited an electrical conductivity of
2.79 S cm1 and a good thermal stability (300 C), which suggests their applicability in fabricating
high temperature electronic devices. Furthermore, electrochemical studies of PEDOTS modified glassy
carbon electrodes (GCEs) showed an oxidation peak of ascorbic acid at a lower potential of 0.046 V with
a peak current about 10 times (91.68 mA) higher than that of the bare GCE with excellent electrode
stability, proposing that it can be used as a steady electrode for the electro-catalytic oxidation of similar
molecules
dispersible electrically conducting poly(3,4-ethylenedioxythiophene) nanospindles (PEDOTSs). PEDOTSs
were formed during the polymerization of the spindle shaped liquid crystalline phase of “EDOT–PDPSA”
which was formed by the specific interactions of 3,4-ethylenedioxythiophene (EDOT) with 3-pentadecyl
phenol-4-sulphonic acid (PDPSA). Liquid crystalline phases were characterized by Polarized Light
Microscopic (PLM) analyses, rheology and XRD. Morphology and solid state ordering of conducting
nanospindles were characterized by SEM, TEM and XRD. PEDOTSs exhibited an electrical conductivity of
2.79 S cm1 and a good thermal stability (300 C), which suggests their applicability in fabricating
high temperature electronic devices. Furthermore, electrochemical studies of PEDOTS modified glassy
carbon electrodes (GCEs) showed an oxidation peak of ascorbic acid at a lower potential of 0.046 V with
a peak current about 10 times (91.68 mA) higher than that of the bare GCE with excellent electrode
stability, proposing that it can be used as a steady electrode for the electro-catalytic oxidation of similar
molecules
In this study, we propose a strategy to offset charge trapping and to enhance the confinement of excitons in the emissive layer of white electroluminescent copolymer using a luminogen with aggregation-induced emission enhancement (AIEE).... more
In this study, we propose a strategy to offset charge trapping and to enhance the confinement of excitons in
the emissive layer of white electroluminescent copolymer using a luminogen with aggregation-induced
emission enhancement (AIEE). The fluorenone-based luminogen, 2,7-bis(9H-fluoren-9-one-2yl)-9,9-
dihexylfluorene (FF) that exhibited yellow emission with AIEE property is copolymerized with 9,9-
dihexylfluorene in different compositions to tune the emission color. White-light emission is
demonstrated in a copolymer FF-0.25, which contained 0.25% of FF in the polymer backbone.
Interestingly, the copolymers exhibited enhanced emission upon aggregation in thin film, even in low FF
composition. OLEDs fabricated from the copolymer FF-0.25 elicited a white electroluminescence with
Commission Internationale de l'Eclairage (CIE) coordinates of 0.30, 0.31 with a power efficiency of 4.12
lm W1. FF-0.25 showed very low charge trapping compared to other white emitting single polymer
OLEDs reported to date. The reduced charge carrier trapping is attributed to the positioning of energy
levels in the copolymer that resulted in almost equal electron- and hole-injection barriers. A theoretical
investigation on the copolymers of FF revealed the presence of an ambipolar property and low exciton
binding energy implicit of efficient formation and confinement of excitons within the emissive layer. The
system represents the first ambipolar white electroluminescent polymer designed by using an AIEE
luminogen.
the emissive layer of white electroluminescent copolymer using a luminogen with aggregation-induced
emission enhancement (AIEE). The fluorenone-based luminogen, 2,7-bis(9H-fluoren-9-one-2yl)-9,9-
dihexylfluorene (FF) that exhibited yellow emission with AIEE property is copolymerized with 9,9-
dihexylfluorene in different compositions to tune the emission color. White-light emission is
demonstrated in a copolymer FF-0.25, which contained 0.25% of FF in the polymer backbone.
Interestingly, the copolymers exhibited enhanced emission upon aggregation in thin film, even in low FF
composition. OLEDs fabricated from the copolymer FF-0.25 elicited a white electroluminescence with
Commission Internationale de l'Eclairage (CIE) coordinates of 0.30, 0.31 with a power efficiency of 4.12
lm W1. FF-0.25 showed very low charge trapping compared to other white emitting single polymer
OLEDs reported to date. The reduced charge carrier trapping is attributed to the positioning of energy
levels in the copolymer that resulted in almost equal electron- and hole-injection barriers. A theoretical
investigation on the copolymers of FF revealed the presence of an ambipolar property and low exciton
binding energy implicit of efficient formation and confinement of excitons within the emissive layer. The
system represents the first ambipolar white electroluminescent polymer designed by using an AIEE
luminogen.
tRobust fibrillar network of hydrogels entrapped with silver nanoparticles were prepared by in situ poly-merization of acrylic acid and reduction of silver nitrate using amidodiol as cross-linking cum reducingagent under ambient... more
tRobust fibrillar network of hydrogels entrapped with silver nanoparticles were prepared by in situ poly-merization of acrylic acid and reduction of silver nitrate using amidodiol as cross-linking cum reducingagent under ambient conditions. Silver nanoparticle-entrapped polyacrylic acid–amidodiol hydrogels(SPAGs) were characterized by UV–visible spectroscopy, SEM, TEM, XRD and rheology. Further, catalyticactivities of SPAGs were studied using dyes such as methylene blue, rhodamine 6G and crystal violet.Effects of temperature and pH on the reduction process were studied. The activation energy for thereduction process was calculated and found to be decreased by ∼10 kJ/mol in the SPAG-catalysed reac-tion. In addition, SPAGs showed excellent reusability, easy separation, high rate constant and absence ofinduction period. All these results suggested SPAGs as a promising catalyst for the reduction of organicmolecules.