Electrical characterization of Au/poly (linoleic acid)-g-poly(methyl methacrylate) (PLiMMA)/n-Si diode in dark and under illumination

Gokcen, Muharrem/0000-0001-9063-3028;WOS: 000345998300003In this study, poly (linoleic acid)-g-poly(methyl methacrylate) (PLiMMA) graft copolymer is used as an interfacial layer in a Schottky diode for the first time. Au/poly (linoleic acid)-g-poly(methyl methacrylate) (PLiMMA)/n-Si diode was fabricated and main electrical characteristics of the diode were investigated using I-V measurements in dark and under illumination at room temperature. Ideality factor (n), barrier height (Phi(B0)) and serial resistance (R-s) values of the diode were found as 2.8, 0.87 eV and 8096 Omega for dark, and 6.3, 0.71 eV and 676 Omega for 100 mW/cm(2) illumination intensity. Also, the reasons of deviation from ideal thermionic emission theory were investigated using Cheung&Cheung method and Card&Rhoderick's function which are used for calculating voltage dependence of barrier height (Phi(B)(V)), series resistance (R-s) and number of surface states (N-ss) of the Au/PLiMMA/n-Si diode. (C) 2014 Elsevier B.V. All rights reserved.Turkish Scientific Research CouncilTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110T884]; Duzce University Research FundDuzce University [2014.05.02.216, 2014.05.02.233, 2014.05.03.234, 2014.05.03.248]This work was supported financially by the Turkish Scientific Research Council (Grant Number: 110T884), Duzce University Research Fund (Grant Numbers: 2014.05.02.216, 2014.05.02.233, 2014.05.03.234, 2014.05.03.248)

Synthesis of a novel macromonomer initiator for atom transfer radical polymerization: Self condensing and graft copolymerization

A new macromonomer initiator for atom transfer radical polymerization (ATRP-MIM) based on polyethylene glycol (Mn= 660 Da) (PEG) was synthesized by the reaction of hydroxyl end of the mono-methacryloyl polyethylene glycol with 2-bromopropanoyl chloride leading to methacryloyl polyethylene glycol 2-bromopropanoyl ester (v-PEG-Br). Poly(ethylene glycol) functionalized with methacrylate at one end was reacted with 2-bromopropionyl chloride to form a macromonomeric initiator for ATRP. Self condensing ATRP-MIM polymerization yielded branched PEG with low cross-linked fraction (3-29 wt%). In the same polymerization condition, self condensing ATRP-MIM polymerization was found faster than that of conventional free radical macromonomer initiators which behave as macro crosslinker, macro initiator and macromonomer. Besides the PEG obtained has still unreacted double bonds and halides leading to the further branching. In the second step, ATRP of methyl methacrylate was initiated by the MIM-ATRP using the copper coordination complex CuBr / N,N,N’,N’,N’’-pentamethyl diethylenetriamine (PMDETA). The ATRP-MIM and the chloroform soluble branched polymers obtained were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). Variation of gel polymer content, molecular weight of the soluble parts and conversion of the monomers with the changing polymerization conditions were also discussed.A new macromonomer initiator for atom transfer radical polymerization (ATRP-MIM) based on polyethylene glycol (Mn= 660 Da) (PEG) was synthesized by the reaction of hydroxyl end of the mono-methacryloyl polyethylene glycol with 2-bromopropanoyl chloride leading to methacryloyl polyethylene glycol 2-bromopropanoyl ester (v-PEG-Br). Poly(ethylene glycol) functionalized with methacrylate at one end was reacted with 2-bromopropionyl chloride to form a macromonomeric initiator for ATRP. Self condensing ATRP-MIM polymerization yielded branched PEG with low cross-linked fraction (3-29 wt%). In the same polymerization condition, self condensing ATRP-MIM polymerization was found faster than that of conventional free radical macromonomer initiators which behave as macro crosslinker, macro initiator and macromonomer. Besides the PEG obtained has still unreacted double bonds and halides leading to the further branching. In the second step, ATRP of methyl methacrylate was initiated by the MIM-ATRP using the copper coordination complex CuBr / N,N,N’,N’,N’’-pentamethyl diethylenetriamine (PMDETA). The ATRP-MIM and the chloroform soluble branched polymers obtained were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). Variation of gel polymer content, molecular weight of the soluble parts and conversion of the monomers with the changing polymerization conditions were also discussed

Synthesis and Characterization of Poly(linoleic acid)-g-poly(Nisopropylacrylamide)-g-poly (D, L-lactide) Graft Copolymers by Onepot Polymerization Method

Bu çalışmada, Otookside polimerik linoleik asit peroksit (PLina)’nın halka açılma polimerizasyonu ve serbestradikal polimerizasyonu bir arada kullanılarak tek adımda (one-pot) üç bloklu graft kopolimerler sentezlendi.Poli(linoleik asit)-g-poli(N-isopropilakrilamit)-g-poli(D,L-laktid) yapısına sahip graft kopolimerler; PLina’nınana zincirinde bulunan peroksit grupları ile N-isopropilakrilamit (NIPAM) monomeriyle serbest radikalpolimerizasyonu ve PLina’nın karboksilik asit grupları ile D,L-laktid (LA) monomeri arasındaki halka açılmapolimerizasyonunun bir arada (one-pot) kullanılmasıyla sentezlendiler. One-pot polimerizasyon reaksiyonunaetki eden polimerizasyon süresi, başlatıcı konsantrasyonu ve monomer konsantrasyonu gibi temel parametrelerincelendi. Elde edilen graft kopolimerlerin karakterizasyonları 1H NMR ve GPC teknikleri kullanılarak yapıldıIn this study, one-pot three-block graft copolymers were synthesized using a combination of ring openingpolymerization and free radical polymerization of Auto-oxidized polymeric linoleic acid peroxide (PLina). Graftcopolymers with poly(linoleic acid)-g-poly(N-isopropylacrylamide)-g-poly(D,L-lactide) structure weresynthesized the free radical polymerization with N-isopropylacrylamide (NIPAM) in monomer the main chain ofPLina and the ring opening polymerization of the D, L-lactide (LA) monomer with carboxylic acid groups ofPLina with together. The basic parameters such as polymerization time, initiator concentration and monomer concentration affecting the one-pot polymerization reaction were investigated. Characterization of the obtainedgraft copolymers were carried out using 1H NMR and GPC techniques

Synthesis and characterization of poly(N-isopropyl acryl amide)-g-poly(LINOLEIC ACID)/poly(linolenic acid) graft copolymers

To diversify edible oil thermoresponsive polymer composites, polymeric linoleic acid peroxide (PLina) and polymeric linolenic acid peroxide (PLinl) were obtained by the autoxidation of linoleic acid (Lina) and linolenic acid (Linl), respectively. The autoxidation of Lina and Linl under air at room temperature rendered waxy soluble polymeric peroxide, having a soluble fraction in chloroform of more than 91 wt% and containing up to 1.0 wt% of peroxide. The soluble polymeric oil macro-peroxide was used to initiate the free radical polymerization of N-isopropylacrylamide, NIPAM, resulting in PLina-g-PNIPAM and PLinl-g-PNIPAM graft copolymers, respectively. The PNIPAM content of the graft copolymers was calculated using the elemental nitrogen analysis of graft copolymers. Thermal analysis, FTIR, 1H NMR, and SEM techniques were used in the characterization of the products. The hydrophobic effect of the fatty acid macro peroxides on the thermal response rate of the graft copolymers was investigated by means of swelling-deswelling behaviors in response to temperature change. They have a thermoresponsive character and exhibit a volume phase transition at approximately 27-30 °C, which is 1-4 °C lower than that of pure PNIPAM. A plastizer effect of PLina and PLinl in graft copolymers was observed, indicating a lower glass transition temperature than that of pure PNIPAM. © 2010 AOCS.Fundamental Research Fund of Shandong University: 2008-70-01-01 108T423, 109T029Acknowledgments This work was financially supported by TUBI-TAK (grant nos. 109T029 and 108T423), Zonguldak Karaelmas University Research Fund (grant no. 2008-70-01-01), and Düzce University Research Fund

Investigation of electrical and photovoltaic properties of Au/poly(propylene glycol)-b-polystyrene/n-Si diode at various illumination intensities

Gokcen, Muharrem/0000-0001-9063-3028WOS: 000333484600005Electrical and photovoltaic properties of Au/poly(propylene glycol)-b-polystyrene/n-Si diode were investigated under various illumination intensities. Field emission scanning electron microscope micrographs of the interfacial polymer layer were provided for verification of the nano-fibre pattern. The current-voltage (I-V) measurements of the diode in the dark and under various illumination intensities (50-250 mW/cm(2)) were carried out and the main electrical parameters of the diode such as leakage current (I-0), ideality factor (n), zero-bias barrier height (phi(B0)), series and shunt resistance (R-s and R-sh), density of surface states (N-ss), open circuit voltage (V-oc) and short-circuit current (I-sc) were obtained in these conditions.Turkish Scientific Research CouncilTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110T884]; Duzce University Scientific Research ProjectDuzce University [2011.05.03.068, 2011.05.HD.026, 2012.05.02.110, 2012.05.HD.052]This work is supported financially by Turkish Scientific Research Council [grant number: 110T884], Duzce University Scientific Research Project [project numbers 2011.05.03.068, 2011.05.HD.026, 2012.05.02.110, 2012.05.HD.052]