Sanjeev K. Manohar

All‐Organic Vapor Sensor Using Inkjet‐Printed Reduced Graphene Oxide

Described herein is a flexible and lightweight chemiresistormade of a thin film composed of overlapped and reducedgraphene oxide platelets (RGO film), which were printedonto flexible plastic surfaces by using inkjet techniques. TheRGO films can reversibly and selectively detect chemicallyaggressivevapors suchasNO

Oxidative Template for Conducting Polymer Nanoclips

Bulk quantities of electronic conducting polymers such as polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene), having an unusual 2D nanoclip-like morphology is described using a general oxidative template assembly route which is orchestrated by an insoluble complex formed between an anionic oxidant (S(2)O(8)(2-)) and a cationic surfactant.

Polyaniline: Oriented Films and Fibers

Abstract The dependency of the conductivity of polyaniline (emeraldine oxidation state) on its molecular weight has been determined. Uni- and biaxially oriented films and uniaxially oriented fibers of emeraldine base have been studied and the dependency of their degree of crystallinity, tensile strength, and conductivity (after doping) on draw ratio has been determined.

Polyaniline: Pernigranile, an isolable intermediate in teh conventional chemical synthesis of emeraldine

Abstract The conventional chemical oxidative polymerization of aniline to polyaniline in the emeraldine oxidation state using acidic ammonium peroxydisulfate (aniline: peroxydisulfate ≈ 4:1; aq. 1. ON HCl; ≈0 °C) was found to proceed via the intermediacy of the fully oxidized pernigraniline oxidation state (readily isolable as the base form). The intermediacy of the pernigraniline oxidation state was first detected by using a novel potential profiling technique in which the oxidation potential of the system was continuously monitored as a function of polymerization time.

Catalyst-Free Synthesis of Oligoanilines and Polyaniline Nanofibers Using H2O2

Nanofibers of polyaniline and oligoanilines of controlled molecular weight, e.g., tetraaniline, octaaniline, and hexadecaaniline, are synthesized using a versatile high ionic strength aqueous system that permits the use of H(2)O(2) with no added catalysts as a mild oxidizing agent. Films of oligoanilines deposited on plastic substrates show a robust and reversible chemiresistor response to NO(2) vapor at room temperature in ambient air (100-5 ppm).

Flexible, All-Organic Chemiresistor for Detecting Chemically Aggressive Vapors

Chemiresistors made of thin films of single-walled carbon nanotube (CNT) bundles on cellulosics (paper and cloth) can detect aggressive oxidizing vapors such as nitrogen dioxide and chlorine at 250 and 500 ppb, respectively, at room temperature in ambient air without the aid of a vapor concentrator. Inkjet-printed films of CNTs on 100% acid-free paper are significantly more robust than dip-coated films on plastic substrates. Performance attributes include low sensor-to-sensor variation, spontaneous signal recovery, negligible baseline drift, and the ability to bend the sensors to a crease without loss of sensor performance.

Facile synthesis of single-crystal and controllable sized silver nanoparticles on the surfaces of polyacrylonitrile nanofibres

A simple method has been demonstrated for the synthesis of single-crystal and controllable sized silver nanoparticles (Ag NPs) homogeneously distributed on the surfaces of polyacrylonitrile (PAN) nanofibres via electrospinning followed by UV irradiation. Keeping the concentration of PAN at 7 wt%, the diameters of the monodisperse single-crystal Ag NPs can be adjusted from 3.5 to 10 nm by varying the molar ratio of silver nitrate to PAN (in terms of the repeating unit: AN). Transmission electron microscopy (TEM), field emitting scanning electron microscopy (FESEM) and x-ray diffraction (XRD) are used to characterize the products.

Chemical synthesis of PEDOT nanofibers

A one-step, room-temperature method is described to chemically synthesize bulk quantities of microns long, 100-180 nm diameter nanofibers of electrically conducting poly(3,4-ethylenedioxythiophene)(PEDOT) in the form of powders, or as optically transparent, substrate-supported films using a V2O5 seeding approach.

Polyaniline: Synthesis and properties of pernigraniline base

Abstract The most highly oxidized polyaniline, in the form of pernigraniline base, can be synthesized as an analytically and oxidatively pure solid (powder or large free-standing films) by the controlled oxidation of emeraldine base by m -chloroperbenzoic acid or directly from aniline by oxidative polymerization with (NH 4 ) 2 S 2 O 8 . In the first method, the emeraldine oxidation state is converted directly to the pernigraniline oxidation state without passing through any intermediate discrete oxidation state at the molecular level. Treatment of perigraniline base with aqueous HCl results not in a protonated form of pernigraniline but in reductive ring chlorination to give the emeraldine oxidation state.

N-substituted derivatives of polyaniline

Fully N-methylated polyaniline was obtained analytically pure by the oxidative polymerization of C6H5N (CH3) (H) with (NH4)2S2O8 in 1.0M aqueous HCl. The resulting black-green polymer (σ ∼10−4 s/cm) was shown to have a similar backbone structure to parent polyaniline, and upon heating, lost HCl and H2O, yielding a black-brown solid, (σ < 10−8 s/cm) containing ∼14% oxidized groups. “Pseudo-protonic” acid doping of “emeraldine” base with neat (CH3)2SO4 yielded polymers whose extent of doping could be monitored continuously. The ∼50% methylated “emeraldine” base (σ = ∼10−2 s/cm) had a χPauli approximately half that of 50% proton doped “emeraldine” base, consistent with the symmetrically effect of the methyl groups.