Flexible thiophene polymers: a concerted macromolecular architecture for dielectrics

2016 ◽  
Vol 7 (17) ◽  
pp. 2929-2933 ◽  
Author(s):  
Xiaodong Yin ◽  
Yali Qiao ◽  
Matthew R. Gadinski ◽  
Qing Wang ◽  
Chuanbing Tang
Keyword(s):  
Dielectric Properties ◽  
Side Chains ◽  
Free Standing ◽  
Polymer Backbone ◽  
Macromolecular Architecture

Highly flexible and transparent free-standing films can be readily obtained from oligothiophene-containing norbornene polymers and their hydrogenated derivatives prepared by ROMP. The rigidness/softness of the polymer backbone and polar side chains dictate dielectric properties.

scholarly journals Variation of the Side Chain Branch Position Leads to Vastly Improved Molecular Weight and OPV Performance in 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene/2,1,3-benzothiadiazole Copolymers

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Robert C. Coffin ◽  
Christopher M. MacNeill ◽  
Eric D. Peterson ◽  
Jeremy W. Ward ◽  
Jack W. Owen ◽  
...  
Keyword(s):  
Thin Film ◽  
Molecular Weight ◽  
Thin Film Transistor ◽  
Power Conversion ◽  
Hole Mobility ◽  
Side Chain ◽  
Side Chains ◽  
Absorption Profile ◽  
Polymer Backbone ◽  
Chain Branch

Through manipulation of the solubilizing side chains, we were able to dramatically improve the molecular weight(Mw)of 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene (BDT)/2,1,3-benzothiadiazole (BT) copolymers. When dodecyl side chains (P1) are employed at the 4- and 8-positions of the BDT unit, we obtain a chloroform-soluble copolymer fraction withMwof 6.3 kg/mol. Surprisingly, by moving to the commonly employed 2-ethylhexyl branch (P2),Mwdecreases to 3.4 kg/mol. This is despite numerous reports that this side chain increases solubility andMw. By moving the ethyl branch in one position relative to the polymer backbone (1-ethylhexyl,P3),Mwis dramatically increased to 68.8 kg/mol. As a result of thisMwincrease, the shape of the absorption profile is dramatically altered, withλmax= 637 nm compared with 598 nm forP1and 579 nm forP2. The hole mobility as determined by thin film transistor (TFT) measurements is improved from~1×10−6 cm2/Vs forP1andP2to7×10−4 cm2/Vs forP3, while solar cell power conversion efficiency in increased to2.91%forP3relative to0.31%and0.19%forP1andP2, respectively.

The Mobility of Tryptophan and Dansyl Fluorophores in Labelled Poly(N-ethylacrylamide) and Poly(N-ethylmethacrylamide)

1993 ◽  
Vol 58 (10) ◽  
pp. 2383-2395 ◽  
Author(s):  
František Mikeš ◽  
Drahomír Výprachtický ◽  
Jan Pecka
Keyword(s):  
Conformational Changes ◽  
High Viscosity ◽  
Side Chains ◽  
Fluorescence Depolarization ◽  
Polymer Backbone ◽  
Short Side ◽  
Low Viscosity ◽  
Viscosity Range ◽  
Methylene Groups ◽  
Intramolecular Association

The mobility of tryptophan fluorophore in N-butyl-Nα-acetyltryptophanamide and in side chain of labelled poly(N-ethylacrylamide) and poly(N-ethylmethacrylamide) was investigated by the fluorescence depolarization method. The mobility of the fluorophore in the low-molecular-weight model is much higher than in side chains of the polymers. Different steric hindrance by the polymer backbone can explain the higher mobility of the fluorophore in poly(N-ethylacrylamide) and in poly(N-ethylmethacrylamide). The mobility of 5-dimethylamino-1-naphthalenesulfonamide (dansyl) fluorophore in side chains of labelled poly(N-ethylmethacrylamide) in the high-viscosity range increases with increasing number of methylene groups in side chains. The low-viscosity range, the rate s of conformational changes in short side chains (n = 2 - 7) are approximately constant and significantly decrease in long side chains (n = 10, 12). The drop in the rates is probably due to intramolecular association of the long hydrophobic chains in water.

Investigation of dielectric properties of free standing electrospun nonwoven mat

2017 ◽  
Vol 135 (16) ◽  
pp. 46121 ◽  
Author(s):  
Jitendra Tahalyani ◽  
Suwarna Datar ◽  
Kandasubramanian Balasubramanian
Keyword(s):  
Dielectric Properties ◽  
Free Standing

Mechanically strong, fluorescent hydrogels from zwitterionic, fully π-conjugated polymers

2014 ◽  
Vol 50 (64) ◽  
pp. 8930-8933 ◽  
Author(s):  
Einat Elmalem ◽  
Frank Biedermann ◽  
Maik R. J. Scherer ◽  
Alexandros Koutsioubas ◽  
Chris Toprakcioglu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Conjugated Polymer ◽  
Side Chains ◽  
Polymer Backbone

Mechanically strong supramolecular hydrogels can be obtained by combining a rigid, fully π-conjugated polymer backbone and zwitterionic side chains.

Broadening Absorption in Conductive Polymers through Cross-linkable Side Chains in a Nonconjugated Polymer Backbone

2010 ◽  
Vol 43 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Arpornrat Nantalaksakul ◽  
Kothandam Krishnamoorthy ◽  
S. Thayumanavan
Keyword(s):  
Conductive Polymers ◽  
Side Chains ◽  
Polymer Backbone

scholarly journals Rational Design of Donor Acceptor Based Semiconducting Copolymers with High Dielectric Constant

2020 ◽  
Author(s):  
Aiswarya Abhisek Mohapatra ◽  
Yifan Dong ◽  
Puttaraju Boregowda ◽  
Ashutosh Mohanty ◽  
Aditya Sadhanala ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Organic Semiconductors ◽  
Density Functional ◽  
Rational Design ◽  
Dielectric Constants ◽  
Side Chains ◽  
Free Charge ◽  
Coulombic Interaction ◽  
Polymer Backbone ◽  
Donor Acceptor

<div> <div> <div> <p>An efficient photogeneration of free charge carriers has long been recognized as the paramount challenge in organic photovoltaic (OPV) devices. The low dielectric constant organic semiconductors fall short to reduce strong Coulombic interaction of tightly bound exciton and hence lead to a loss mechanism in OPVs due to charge-carrier recombination. To circumvent this problem, we adopt a strategy to enhance the dielectric constant of organic semiconductors by incorporating tetraethyleneglycol (TEG) side-chains. We report synthesis of three new semiconducting copolymers by combining thiophene substituted diketopyrrolopyrrole (TDPP) monomer with three other monomeric units with varying electron donating strength: benzodithiophene (BBT-3TEG-TDPP), TDPP (TDPP-3TEG-TDPP) and naphthalene diimide (PNDITEG-TDPP). BBT-3TEG-TDPP and PNDITEG-TDPP showed highest dielectric constants (~ 5) at 1MHz frequency suggesting efficient contribution of dipolar polarization from TEG side-chains. To understand the electronic contribution of the polymer backbone and the polarity of TEG side-chains, and the resulting enhancement of the dielectric constant, we further performed first-principles density functional theory calculations. Single-component organic solar cells (OSC) fabricated utilizing these polymers resulted in poor performance which is attributed to the absence of free charge generation. Furthermore, transient absorption spectroscopy studies show low exciton diffusion length as observed in donor-acceptor type conjugated polymers. Our results suggest that, the strategy of enhancing dielectric constant with polar side-chains is not sufficient to reduce Coulombic interaction between hole and electron in OSCs. </p> </div> </div> </div>

Synthesis of Polysiloxanes Bearing Cyclic Carbonate Side Chains. Dielectric Properties and Ionic Conductivities of Lithium Triflate Complexes

1994 ◽  
Vol 27 (15) ◽  
pp. 4076-4079 ◽  
Author(s):  
Zhenya Zhu ◽  
Alison G. Einset ◽  
Chia-Yu Yang ◽  
Wei-Xiao Chen ◽  
Gary E. Wnek
Keyword(s):  
Dielectric Properties ◽  
Ionic Conductivities ◽  
Cyclic Carbonate ◽  
Side Chains ◽  
Lithium Triflate

scholarly journals Temperature dependant structural changes in thin films of random semifluorinated PMMA copolymers

2013 ◽  
Vol 28 (S2) ◽  
pp. S144-S160 ◽  
Author(s):  
Dieter Jehnichen ◽  
Peter Friedel ◽  
Romy Selinger ◽  
Andreas Korwitz ◽  
Martin Wengenmayr ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Separation ◽  
Structural Changes ◽  
Bulk Material ◽  
Fluorine Content ◽  
Film Surface ◽  
Phase Behaviour ◽  
Side Chain ◽  
Side Chains ◽  
Polymer Backbone

Semifluorinated (SF) side chain polymers show phase separation between polymer backbone and SF side chains. Due to strong interaction between SF segments the side chains determine the structure behaviour strongly, often resulting in layered structures in which backbones and layers of SF side chains alternate. The interest in this work was directed to find out the dependence of these structures on concentration of SF side chains. Thin films of random copolymers consisting of methylmethacrylate (MMA) and semifluorinated side chain methacrylate (SFMA) segments and with different fluorine content in the perfluoroalkyl side chains (abbreviated as H10F10 and H2F8) were prepared by spin-coating. Phase separation and structure changes were initiated by external subsequent annealing. Corresponding bulk material served as basic information. Generation of ordered structures and variation of film parameters were observed using different X-ray scattering methods (XRR, GIWAXS, and GISAXS). The phase behaviour in bulk is governed by the SF side chain amount and their specific fluorine content which control the self-organization tendency of SF side chains. Additionally, the confinement in thin films generates an orientation of side chains normally to film surface.

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