Ali Cirpan

Synthesis and photophysical property of well-defined donor–acceptor diblock copolymer based on regioregular poly(3-hexylthiophene) and fullerene

A new, well-defined diblock copolymer (P3HT-b-C60) based on regioregular poly(3-hexylthiophene) (P3HT) and fullerene was synthesized. First, regioregular P3HT was synthesized through Grignard metathesis polymerization, and then methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) were copolymerized by using an end-functionalized P3HT as a macroinitiator for the atom transfer radical polymerization to yield a diblock copolymer (P3HT-b-P(MMA-r-HEMA)). A fullerene derivative functionalized with carboxylic acid, [6,6]-phenyl-C61-butyric acid (PCBA), was then chemically linked to the HEMA unit in the second block (P(MMA-r-HEMA)) to produce a diblock copolymer with the second block containing fullerenes. Annealing thin films of the copolymer revealed nanometer-scale phase separation, a more suitable morphology for enabling excitons generated in the P3HT domain to more efficiently reach the donor–acceptor interface, relative to simple blends of P3HT and C60. As a result, photoluminescence of the P3HT-b-C60diblock copolymer in the films showed a complete quenching of photoluminescence of P3HT, which is indicative of charge transfer between P3HT and fullerene.

Electrochromic devices based on soluble and processable dioxythiophene polymersElectronic supplementary information (ESI) available: details of the synthesis of PProDOT(CH2OC18H37)2 and PProDOT(CH2OEtHx)2 and their polymerization. See http://www.rsc.org/suppdata/jm/b3/b306365h/

Reflective and absorptive/transmissive polymer electrochromic devices (ECDs) composed of spray-coated films of poly(3,3-bis(octadecyloxymethyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine) (PProDOT(CH2OC18H37)2) and poly(3,3-bis(2-ethylhexyloxymethyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine) (PProDOT(CH2OEtHx)2) layers as cathodically coloring polymers and poly(3,6-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9-methyl-9H-carbazole) (PBEDOT-NMeCz) as the anodically coloring polymer have been constructed and evaluated. These devices exhibit low switching voltages (±1.2 V), high visible contrast values, sub-second switching times, and high switching stability in atmospheric conditions. The reflective ECD comprising PProDOT(CH2OEtHx)2 as the active layer demonstrates an unusual electrochromic behavior. By regulating the applied voltage, a high reflectance contrast of greater than 70% ΔT was achieved in the NIR region (2 µm) without any noticeable color change of the device.

Transparent and flexible supercapacitors with single walled carbon nanotube thin film electrodes.

We describe a simple process for the fabrication of transparent and flexible, solid-state supercapacitors. Symmetric electrodes made up of binder-free single walled carbon nanotube (SWCNT) thin films were deposited onto polydimethylsiloxane substrates by vacuum filtration followed by a stamping method, and solid-state supercapacitor devices were assembled using a gel electrolyte. An optical transmittance of 82% was found for 0.02 mg of SWCNTs, and a specific capacitance of 22.2 F/g was obtained. The power density can reach to 41.5 kW · kg(-1) and shows good capacity retention (94%) upon cycling over 500 times. Fabricated supercapacitors will be relevant for the realization of transparent and flexible devices with energy storage capabilities, displays and touch screens in particular.

Immobilization of invertase in conducting copolymers of 3-methylthienyl methacrylate

Immobilization of invertase in conducting copolymer matrices of 3-methylthienyl methacrylate with pyrrole and thiophene was achieved by constant potential electrolysis using sodium dodecyl sulfate (SDS) as the supporting electrolyte. Polythiophene (PTh) was also used in entrapment process for comparison. Kinetic parameters, Michaelis-Menten constant, K(m), and the maximum reaction rate, V(max), were investigated. Operational stability and temperature optimization of the enzyme electrodes were also examined.

Synthesis and characterization of conducting polymers containing polypeptide and ferrocene side chains as ethanol biosensors

A novel approach for the fabrication of a biosensor from a conducting polymer bearing polypeptide segments and ferrocene moieties is reported. The approach involves the electrochemical copolymerization of the electroactive polypeptide macromonomer and independently prepared ferrocene imidazole derivative of dithiophene, on the electrode surface. The polypeptide macromonomer was synthesized by the simultaneous formation of N-carboxyanhydride (NCA) and ring opening polymerization of N-Boc-L-lysine (α-amino acid of the corresponding NCA) using an amino functional bis-EDOT derivative (BEDOA-6) as an initiator. Alcohol oxidase was then covalently immobilized onto the copolymer coated electrode using glutaraldehyde as the crosslinking agent. The intermediates and final conducting copolymer before and after enzyme immobilization were fully characterized by FT-IR, 1H-NMR, GPC, cyclic voltammetry, SEM and EIS analyses. The newly designed biosensor which combined the advantages of each component was tested as an ethanol sensing system offering fast response time (9 s), wide linear range (0.17 mM and 4.25 mM) and low detection limit (0.28 mM) with a high sensitivity (12.52 μA mM−1 cm−2). Kinetic parameters KappM and Imax were 2.67 mM and 2.98 μA, respectively. The capability of the biosensor in determining ethanol content in alcoholic beverages was also demonstrated.

Preparation of Metallic Line Patterns from Functional Block Copolymers

A simple route for the preparation of nanoscopic metallic line patterns from functional block copolymers (BCPs) containing poly(2-vinylpyridine) or poly(methyl methacrylate) blocks is demonstrated. The time evolution of the surface morphologies of BCP thin films exposed to solvent vapors is studied to optimize the conditions for generating BCP microdomains oriented parallel or normal to the substrate. BCP templates are prepared by film reconstruction or by removal of one of the copolymer microdomains, depending on the properties of the functional BCPs. Finally, metallic line patterns are prepared by either electrochemical etching or direct metal deposition and lift-off processes using the BCP templates.

A Novel and Effective Surface Design: Conducting Polymer/β-Cyclodextrin Host–Guest System for Cholesterol Biosensor

The combination of supramolecules and conducting polymers (CPs) has gained much attention for the development of new immobilization matrices for biomolecules. Herein, an amperometric biosensor based on a novel conducting polymer, poly(2-(2-octyldodecyl)-4,7-di(selenoph-2-yl)-2H-benzo[d][1,2,3]triazole)) (PSBTz) and β-cyclodextrin (β-CD) for the detection of cholesterol, was constructed. The PSBTz film with β-CD was deposited on a graphite electrode by electropolymerization technique to achieve a suitable matrix for enzyme immobilization. Moreover, to justify the immobilization, alkyl chain containing conducting polymer (PSBTz) was designed, synthesized and electrochemically polymerized on the transducer surface. Alkyl chains in the structure of SBTz and hydroxyl groups of β-CD contributed to effective immobilization while protecting the suitable orientation of the biomolecule. Cholesterol oxidase (ChOx) was covalently immobilized onto the modified surface using N,N′-carbonyldiimidazole (CDI) as the cross-linking agent. After successful immobilization, amperometric biosensor responses were recorded at −0.7 V vs Ag/AgCl in phosphate buffer (pH 7.0). The apparent Michaelis-Menten constant (KM(app)), maximum current (Imax), limit of detection (LOD), and sensitivity values were determined: 28.9 μM, 12.1 μA, 0.005 μM, and 5.77 μA/μM cm(2), respectively. The fabricated biosensor was characterized using scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Finally, the prepared biosensor was successfully applied for the determination of cholesterol in blood samples.

Synthesis and electroactivity of pyrrole end-functionalized poly(2-methyl-2-oxazoline)

Poly(2-methyl-2-oxazoline) (PMeOZO) with pyrrole end groups was synthesized by cationic ring polymerization of 2-methyl-2-oxazoline initiated by benzyl bromide and subsequent modification of the halide end group. The structure and electroactivity of the macromonomer thus obtained were confirmed by spectral analysis and cyclic voltametry, respectively. The posssibility of chemical and electrochemical graft copolymerization of PMeOZO with pyrrole was also studied.

Synthesis and characterization of conducting copolymers of thiophene-3-yl acetic acid cholesteryl ester with pyrrole

A new polythiophene containing a cholesteryl side chain in the β-position was chemically polymerised in nitromethane/carbontetrachloride using FeCl3 as the oxidizing agent. Polymerisation was also achieved by constant current electrolysis in dichloromethane. Subsequently, conducting copolymers of thiophene-3-yl acetic acid cholesteryl ester (CM), PCM1 (obtained from chemical polymerisation method) and PCM4 (obtained from constant current electrolysis) with pyrrole were synthesized using p-toluene sulfonic acid and sodium dodecyl sulfate as the supporting electrolytes via constant potential electrolyses. Characterizations of the samples were performed by CV, FTIR, NMR, DSC, TGA and SEM analyses. Electrical conductivities were measured by the four-probe technique.

A novel architecture based on a conducting polymer and calixarene derivative: its synthesis and biosensor construction

In this study, a novel amperometric glucose biosensor based on a selenium comprising conducting polymer and calixarene was developed. Firstly, poly(2-(2-octyldodecyl)-4,7-di(selenoph-2-yl)-2H-benzo[d][1,2,3]triazole), poly((SBTz)) was electrodeposited onto a graphite electrode by an electropolymerization technique. Then, a newly synthesized calixarene and gold nanoparticle (AuNP) mixture was used for the improvement of biosensor characteristics. GOx, as a model enzyme was immobilized on the modified electrode surface. The constructed surface serves as a sufficient immobilization platform for the detection of glucose. Calixarenes and their derivatives may be a favouring agent for enzyme immobilization due to their specific configurations. Moreover, through the covalent binding between the carboxylic groups of the calixarenes and amino groups of the biomolecule, effective enzyme immobilization can be achieved while protecting the well-ordered structure of the enzyme molecule. Amperometric detection was carried out following oxygen consumption at −0.7 V vs. the Ag reference electrode in phosphate buffer (50 mM, pH 6.5). The proposed biosensor showed a linear amperometric response for glucose within a concentration range of 0.005 to 0.5 mM (LOD: 0.004 mM). Kappm and sensitivity were calculated as 0.025 mM and 102 μA mM−1 cm−2, respectively. Scanning Electron Microscopy (SEM) was used to investigate the surface morphologies of successive modifications. Finally, the constructed biosensor was tested successfully to detect glucose in beverage samples.