Nanostructuring of poly(diphenylamine) inside the galleries of montmorillonite organo clay through self-assembly approach.

Gopalan, Anantha Iyengar,Lee, Kwang-Pill,Hong, Mung-Hwa,Santhosh, Padmanabhan,Manesh, Kalayil Manian,Kim, Sang-Ho American Scientific Publishers 2006 Journal of nanoscience and nanotechnology Vol.6 No.6

<P>Hollow spheres of poly(diphenylamine) (PDPA) was prepared by confining PDPA in the galleries of montmorillonite organo clay modified with organoammonium cations (MMT). At first instant, diphenylamine (DPA) was loaded into the galleries of MMT and subjected to subsequent oxidative polymerization to form PDPA. beta-naphthalene sulfonic acid (NSA) was used as medium to influence self-assembly of DPA inside the galleries of MMT. Polymerization of self assembled structure resulted hollow spheres of PDPA inside galleries of MMT. X-ray diffraction analysis (XRD), field emission transmission electron microscopy (FETEM), Fourier transform infra-red spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were used to characterize the composites. Transmission emission microscopy of the composite shows the hollow spherical morphology of PDPA. FT-IR, UV-Visible spectroscopy, conductivity measurement and X-ray photoelectron spectroscopy were used to characterize the PDPA extracted from MMT galleries. PDPA extracted from MMT galleries was found to have difference in electronic property than PDPA formed by the conventional method, due to the confinement effect.</P>

Mild wetting poor solvent induced hydrogen bonding interactions for improved performance in bulk heterojunction solar cells

Gopalan, S. A.,Seo, M. H.,Anantha-Iyengar, G.,Han, B.,Lee, S. W.,Kwon, D. H.,Lee, S. H.,Kang, S. W. Royal Society of Chemistry 2014 Journal of Materials Chemistry A Vol.2 No.7

In this paper, we demonstrate a facile, mild wetting (short residence time) poor solvent [isopropyl alcohol (IPA)] treatment, carried out on the top surface of a spin-cast poly (3-hexylthiopene) (P3HT) and [6,6]-phenyl-C71-butyric acid methyl ester (PCBM) blend film, in order to fabricate high-performance polymer solar cells (PSCs). This method utilizes the hydrophilic and polar/hydrogen bonding interactions of IPA with the blend components (P3HT and PCBM). The photovoltaic (PV) performance of the fabricated PSCs was optimized by utilizing a preheated IPA wetting treatment and devices fabricated with the configuration: ITO/PEDOT: PSS/P3HT:PCBM/M-IPA-T degrees/Al (T degrees: 25 degrees C/45 degrees C/65 degrees C/85 degrees C) (where 'M' stands for modified IPA and 'T' signifies the temperature used for the IPA wetting). Our investigation encompasses electrical, optical, crystalline, and morphological studies on the P3HT: PCBM blend films, modified by preheated IPA, to elucidate the associated enhancements in the PV characteristics and performance. The device fabricated with IPA-85 degrees C (ITO/PEDOT: PSS/P3HT: PCBM/M-IPA-85 degrees C/Al) exhibited the best power conversion efficiency (PCE) of 3.51%, with an open circuit voltage of 0.65 V, a fill factor of 0.52, and a short-circuit current density of 10.20 mA cm(-2). In contrast, the non-modified blend film device showed a PCE of only similar to 3.04%. Ultraviolet-visible absorption studies and X-ray diffraction results suggest that the use of the pre-heated mild-wetting IPA treatment improves the crystallinity and self-organization of the blend layer. We rationalize our findings based on the interactions between IPA and the blend components, due to its high polar and hydrogen bonding Hansen solubility parameters to impart supramolecular assembly of P3HT chains during the blend film formation. This is the first report demonstrating that the poor solvent (IPA) can induce an optimal phase separation in a P3HT: PCBM blend through our proposed mild wetting preheated treatment, toward achieving high-performance PSCs.

Catalytic reduction of 4 -nitrophenol using new Palladium - Copper alloy based heterogeneous nanocatalysts

이현규,( Anantha Iyengar Gopalan ),이광필 한국환경분석학회 2013 제1회 한국분석기술단체 총 연합 합동 심포지엄 Vol.0 No.-

Development of a surface plasmon assisted label-free calorimetric method for sensitive detection of mercury based on functionalized gold nanorods

Anand, Gopalan Sai,Gopalan, Anantha Iyengar,Kang, Shin-Won,Lee, Kwang-Pill The Royal Society of Chemistry 2013 Journal of analytical atomic spectrometry Vol.28 No.4

<P>In this investigation, we established a new sensitive, selective and label free optical method for the detection of mercury ions (Hg<SUP>2+</SUP>) by utilizing cyano (–CN) ligand functionalized gold nanorods (GNRs) based on the surface plasmon resonance (SPR) of the GNRs. The functionalization of the GNRs was specifically done with a –CN group containing polymer, poly(2-aminobenzonitrile) (P2ABN), to preconcentrate the Hg<SUP>2+</SUP> ions on the surface of the GNRs prior to detection. The functionalization of the GNRs was carried out by two approaches. In the first approach, the GNR surface was modified with a porous silica network containing P2ABN (designated as GNR@silica-CN). In the second approach, GNR was modified with P2ABN (designated as GNR@P2ABN). The Hg<SUP>2+</SUP> ion detection strategy involves the preconcentration of Hg ions on the surface of GNR@silica-CN or GNR@P2ABN through the interaction of the –CN groups in P2ABN with Hg<SUP>2+</SUP> ions, reduction to Hg<SUP>0</SUP> atoms by ascorbic acid (AA), and monitoring the SPR of GNRs. The porous network in GNR@silica-CN allows efficient migration of Hg<SUP>0</SUP> to reach the GNR surface and causes effective amalgamation compared to GNR@P2ABN. As a result, GNR@silica-CN exhibits a significant change in the SPR of GNRs over a wide dynamic concentration range (from 50 nM to 5 μM) for Hg<SUP>2+</SUP> ions. The very low detection limit of 1 ppb with GNR@silica-CN for Hg<SUP>2+</SUP> ions suggests its excellent potential for the monitoring and detection of ultra low levels of Hg. In addition, the GNR@silica-CN shows no sensitivity for other environmentally relevant metal ions which confirms the high specificity for Hg<SUP>2+</SUP> ion detection in practical samples. We demonstrated the effectiveness of the present method by detecting Hg<SUP>2+</SUP> ions in spiked water (pond and water) samples. We envisage that this simple, fast and sensitive method will be suitable for environmental monitoring in the future.</P> <P>Graphic Abstract</P><P>A new highly selective sensing strategy for detection of mercury ions has been developed utilizing polymer containing cyano group functionalized gold nanorods. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3ja30300d'> </P>

Preparation and characterization of prospective disulfide based electrode materials for lithium batteries

Dhanusuraman Ragupathy,Anantha Iyengar Gopalan,Kwang-Pill Lee 한국분석과학회 2008 분석과학 Vol.21 No.1

Preparation and characterization of prospective disulfide based electrode materials for lithium batteries

Ragupathy, Dhanusuraman,Gopalan, Anantha Iyengar,Lee, Kwang-Pill The Korean Society of Analytical Sciences 2008 분석과학 Vol.21 No.1

Organic disulfide compounds are having higher theoretical capacity than the conventional cathode material and are considered as the important storage material. Here, we are reporting the preparation of poly (2,2'-dithiodianiline) PDDA/multiwall carbon nanotubes, (MWCNTs) composites under different experimental conditions. Amine functionalized and unfunctionalized MWCNTs were independently used for the preparation of composites. Composites were prepared in the presence of cetyl trimethyl bromide (CTAB), a cationic surfactant, and also in the absence of CTAB. A physical mixture of PDTDA and MWCNTs was formed with unfunctionalized MWCNTs. Grafting of PDDA onto MWCNTs was performed by chemical oxidative polymerization of 2, 2'-dithiodianiline in the presence of amine functionalized MWCNTs. The composites of MWCNTs and PDTDA were characterized for structure, morphology and thermal properties through Fourier transform infrared spectroscopy, Fourier transform Raman spectroscopy, scanning electron microscopy and UV-visible spectroscopy. The composite materials prepared by this method are expected to find applications as electrode materials for lithium batteries.

Synthesis of Magnetic Nanoparticles Incorporated Smart Gel

Li, Jun,Gopalan, Anantha-Iyengar,Lee, Kwang-Pill American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.9

New Titanium Dioxide-Based Heterojunction Nanohybrid for Highly Selective Photoelectrochemical–Electrochemical Dual-Mode Sensors

Nallal, Muthuchamy,Anantha Iyengar, Gopalan,Pill-Lee, Kwang American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.42

<P>A new titanium dioxide (TiO2)-based heterojunction nanohybrid (HJNH) composed of TiO2, graphene (G), poly[3-aminophenylboronic acid] (PAPBA), and gold nanoparticles (Au NPs) was synthesized and designated as TiO2(G) NW@PAPBA-Au HJNH. The TiO2(G) NW@ PAPBA-Au HJNH possesses dual-mode signal photoelectrochemical (PEC) and electrochemical transduction capabilities to sense glucose and glycated hemoglobin (HbAlc) independently. The synthesis of the HJNH material involved 1GAu 11) NIMP two sequential stages: (i) simple electrospinning synthesis of 1%-3111 APH 4. G-embedded TiO2 nanowires [TiO2(G) NWs] and (ii) onestep synthesis of Au NP-dispersed PAPBA nanocomposite (NC) in the presence of TiO2(G) NWs. The as-synthesized TiO2(G) NW@PAPBA-Au HJNH was characterized by field emission scanning electron microscopy, field emission transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared, thermogravimetric analysis, and UV-visible diffuse reflectance spectroscopy. A PEC platform was developed with TiO2(G) NW@PAPBA-Au HJNH for the selective detection of glucose without any enzyme auxiliary. The PEC glucose sensor presents an acceptable linear range (from 0.5 to 28 mM), good sensitivity (549.58 mu A mM(-1) cm(-2)), and low detection limit (0.11 mM), which are suited for diabetes glucose monitoring. Besides, the boronic acid groups in PAPBA were utilized as a host to capture HbAlc. We fabricated the electrochemical HbAlc sensor based on monitoring the electrocatalytic reduction current of hydrogen peroxide produced by HbAlc tethered to the sensor probe. The amperometric electrochemical sensor for HbAlc exhibited linear responses to HbAlc levels from 2.0 to 10% (with a detection limit of 0.17%). Notably, the performances of the fabricated glucose and HbAlc sensors are superior in the dual-signal transduction modes as compared to the literature, suggesting the significance of the newly designed bifunctional TiO2(G) NW@PAPBA-Au HJNH.</P>

Nanomolar detection of dopamine at multi-walled carbon nanotube grafted silica network/gold nanoparticle functionalised nanocomposite electrodes

Komathi, Shanmugasundaram,Gopalan, Anantha Iyengar,Lee, Kwang-Pill Royal Society of Chemistry 2010 The Analyst Vol.135 No.2

<P>This is the first report on ultrahigh sensitive and selective electrochemical detection of nanomolar concentrations of dopamine (DA) in the presence of ascorbic acid (AA) at a modified electrode fabricated with a new functional nanocomposite, comprising of multi-walled carbon nanotube (MWNT) grafted silica network (silica NW) and gold nanoparticles (Au NPs) (MWNT-g-silica NW/Au NPs). The fabrication of MWNT-g-silica NW/Au NPs modified electrodes involves two steps: covalent functionaliztion of MWNT with silica NW and deposition of Au NP. Cyclic voltammetry and differential pulse voltammetry experiments were performed for the individual and simultaneous electrochemical detection of DA (in nanomolar concentrations) and AA. Differential pulse voltammograms at ITO/MWNT-g-silica NW/Au NPs modified electrode (ME) revealed that the current response is linear for DA in the concentration range of 0.1 nM–30 nM with a detection limit of 0.1 nM. This is the lowest detection limit reported for DA. A plausible mechanism is presented for the excellent performance of ITO/MWNT-g-silica NW/Au NPs-ME towards nanomolar detection of DA. The results revealed that MWNT, silica NW and Au NPs in ITO/MWNT-g-silica NW/Au NPs-ME synergistically contribute to the ultrasensitivity and selectivity for the electrochemical detection of nanomolar concentrations of DA in the presence of coexisting species.</P> <P>Graphic Abstract</P><P>The matrix of new nanocomposite, porous silica grafted multi-walled carbon nanotube/Au, electrochemically discriminates dopamine from ascorbic acid at nanomolar concentration levels. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b918335c'> </P>

Fabrication of Gold Nanoflower Anchored Conducting Polymer Hybrid Film Electrode by Pulse Potentiostatic Deposition

Sai-Anand, Gopalan,Gopalan, Anantha Iyengar,Shin-Won Kang,Kwang-Pill Lee IEEE 2013 IEEE electron device letters Vol.34 No.8

<P>In this letter, we report a simple and rapid (~60 s) method to fabricate a new organic-inorganic hybrid film based on poly (di phenyl amine-co-4 amino thiophenol) (designated as PDPAAT) and gold nanoflowers (Au NFs). The fabrication involves a fast facile and pulse potentiostatic approach for the electrodeposition of Au NFs onto PDPAAT. The electrochemical, interfacial, and optical properties of the PDPAAT/Au NF hybrid film electrode are investigated. The superior electroactivity, electrochemical, and interfacial characteristics of the PDPAAT/Au NF electrode suggests its suitability for sensor, electrocatalysis, and diode applications.</P>