Isomeric polythiophene: a promising material for low voltage electronic devices.

In this investigation, we present empirical observations detailing the manifestation of substantial negative capacitance (NC), reaching up to -1 F, within iodine-doped isomeric polythiophene (IPTh-I2). NC observed in our case is not transient but stable enough to be measured for as long as the optimum concentration of the iodine dopant is available. In contrast, undoped isomeric polythiophene (IPTh) manifests a modest positive capacitance ranging from 30 to 60 µF. The concatenation of IPTh-I2 and IPTh in the series results in an augmentation of the total capacitance of the system (∼170 µF), exemplifying a characteristic feature of NC. Conversely, a bilayer configuration consisting of IPTh:IPTh exhibits a reduction in total capacitance by 38%. A notable amplification in the dielectric constant, escalating from 30 in IPTh to approximately 2000 in IPTh-I2, signifies extensive conformational and structural alterations arising from interactions between the doped polymer chain and various iodide species, attributing to the emergence of NC. Furthermore, we document a single-sided p-n junction diode with a low knee voltage (below 0.5 V) as a model device, illustrating the potential of IPTh as a promising material for the design and development of negative capacitance-based field-effect transistors. This research offers avenues for the scientific community to conceive low knee voltage-operating diodes, transistors, supercapacitors, and various other electronic devices based on all-organic semiconductors.

Synthesis, characterization and electro-conducting study of isomeric polythiophene.

Herein we have reported for the first time a one-pot, one step methodology to synthesize isomeric polythiophene (IPTh) possessing 2,2, 2,4 and 5,4 linkages. The method of polymerization of thiophene to IPTh involved reacting thiophene with DDQ in the presence of concentrated H2SO4 at 40 °C and the polymerization is completed in 10 minutes. The synthesized IPTh was characterized by various spectroscopic and microscopic techniques. The formation of polaron and bipolaron in an iodine doped sample (IPTh-I2) has been confirmed by IR, Raman and UV-Vis spectra. The electrical conductivity of the synthesized IPTh and IPTh-I2 have been studied by impedance spectroscopy and found to be ∼10-5 and 10-3 S cm-1 respectively. IPTh exhibits an excellent thermal stability up to 150 °C, and low optical band gap of 3.49 eV suitable for photovoltaic applications. The weight average molecular weight of IPTh has been found to be 18.636 kDa, and it has a better post functionalization capability and hence wider scope than polythiophene (PTh).

Solution and microwave assisted synthesis of ß-Cyclodextrin grafted polyacrylamide: Water treatment and In-vitro drug release study.

The present article reports the application of ß-cyclodextrin grafted polyacrylamides synthesized through solution and microwave assisted polymerization techniques as flocculants and then the employment of partially hydrolyzed products of best grade of each technique in-vitro drug release study of diclofenac sodium. Five different grades of ß-cyclodextrin grafted polyacrylamides by each of solution and microwave assisted polymerization techniques have been synthesized, by varying the monomer concentration. The synthesized polymers have been well characterized and their flocculation performances have been evaluated in kaolin suspension through settling and jar test methods Then the best performing grades of both the techniques have been partially hydrolyzed to prepare three different grades each technique by varying the concentration aqueous NaOH solution. Flocculation efficiencies of these polymers have been investigated in kaolin suspension. Thus best grades of partially hydrolyzed grafted polymers of each technique have been chosen for further study of drug delivery. In-vitro drug release study has been done using diclofenac sodium loaded microbeads prepared by ionic gelation method with two partially hydrolyzed grafted polymers (one from each technique) in phosphate buffer solution (PBS) at 37±0.5 ○C and pH 7.4. The drug load and release have been analyzed by UV-vis spectroscopy.

Synthesis, characterization and application of novel cationic and amphoteric flocculants based on amylopectin.

The synthesis of novel cationic flocculants based on amylopectin (AP), acrylamide (AM) and (3-acrylamidopropyl) trimethylammonium chloride (ATMAC) were done by free radical polymerization using ammonium persulphate (APS) as an initiator. Three different grades of novel cationic flocculants (AP-g-C 1 to AP-g-C 3) were synthesized by varying the proportion of acrylamide and (3-acrylamidopropyl) trimethylammonium chloride monomers. Through the hydrolysis of these flocculants, in presence of NaOH, three different grades of amphoteric polymers (AP-AT-C 1 to AP-AT-C 3) were synthesized. The synthesized polymers were characterized by various methods, namely, infrared spectroscopy, NMR spectroscopy, thermal analysis, viscosity measurement, scanning electron microscopy and X-ray diffractometry. The flocculation performance of AP-g-C and AP-AT-C were studied in kaolin suspension using jar test and settling test methods at neutral pH. Dye (Methylene blue) removal tests were performed using polymer beads and analysed by UV-vis spectroscopy.

Synthesis, characterization and cyclic voltammetric study of copper(II) and nickel(II) polymer chelates.

Graft copolymers based on dextran (Dx) and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS) were synthesized by free radical initiated solution polymerization technique using ceric ammonium nitrate as initiator. These graft copolymers were used to prepare Cu(II) and Ni(II) chelates by reactions with Cu(II) and Ni(II) metal ions respectively. Graft copolymer and metal chelates were characterized by elemental analysis, intrinsic viscosity, FT-IR, scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and powder X-ray diffraction (XRD). Elemental analysis, intrinsic viscosity and FT-IR studies revealed the incorporation of metal ions to form metal chelates. SEM studies showed the change in morphology due to metal incorporation. From AFM studies it was observed that there was increase in Root mean square (RMS) roughness values in case of metal complexes. Metal chelates were observed to be thermally more stable than graft copolymer from TGA. UV-vis spectroscopy study revealed increase in absorbance values and cyclic voltammetric (CV) studies showed more than tenfold increase in redox current due to formation of Cu(II) and Ni(II) metal chelates. The binding constants of each complex determined by using UV-visible spectroscopy revealed that Cu(II) has more binding ability than Ni(II).