Single chain versus single aggregate spectroscopy of conjugated polymers. Where is the border?

2010 ◽  
Vol 12 (37) ◽  
pp. 11770 ◽  
Author(s):  
Hongzhen Lin ◽  
Ralph P. Hania ◽  
Robert Bloem ◽  
Oleg Mirzov ◽  
Daniel Thomsson ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Single Chain

scholarly journals Impact of charge carrier injection on single-chain photophysics of conjugated polymers

2016 ◽  
Vol 108 (26) ◽  
pp. 263301 ◽  
Author(s):  
Felix J. Hofmann ◽  
Jan Vogelsang ◽  
John M. Lupton
Keyword(s):  
Charge Carrier ◽  
Conjugated Polymers ◽  
Carrier Injection ◽  
Single Chain ◽  
Charge Carrier Injection

Influence of Backbone Rigidness on Single Chain Conformation of Thiophene-Based Conjugated Polymers

2013 ◽  
Vol 117 (16) ◽  
pp. 4461-4467 ◽  
Author(s):  
Zhongjian Hu ◽  
Jianhua Liu ◽  
Lauren Simón-Bower ◽  
Lei Zhai ◽  
Andre J. Gesquiere
Keyword(s):  
Conjugated Polymers ◽  
Chain Conformation ◽  
Single Chain

Single-chain polymerization dynamics and conformational mechanics of conjugated polymers

Chem ◽  
2021 ◽  
Author(s):  
Susil Baral ◽  
Chunming Liu ◽  
Udit Kumar Chakraborty ◽  
Kaori Kubo ◽  
Xianwen Mao ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Single Chain ◽  
Chain Polymerization

scholarly journals Advances in Fluorescent Single-Chain Nanoparticles

2017 ◽  
Author(s):  
Julen De-La-Cuesta ◽  
Edurne Gonzalez ◽  
José A. Pomposo
Keyword(s):  
Conjugated Polymers ◽  
Cancer Diagnosis ◽  
Cell Biology ◽  
Polymer Networks ◽  
Imaging Systems ◽  
Single Chain ◽  
Fluorescent Properties ◽  
Biomarker Analysis ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

Fluorophore molecules can be monitored by fluorescence spectroscopy and microscopy which are highly useful and widely used techniques in cell biology, biochemistry and medicine (e.g., biomarker analysis, immunoassays, cancer diagnosis). Several fluorescent micro- and nanoparticle systems based on block copolymer micelles and cross-linked polymer networks, quantum dots, -conjugated polymers, and dendrimers have been evaluated as optical imaging systems. In this review, we highlight recent advances in the construction of fluorescent single-chain nanoparticles (SCNPs) which are valuable artificial soft nano-objects with tunable, small size (as small as 3 nm). In particular, the main methods currently available to endow SCNPs with fluorescent properties are discussed in detail, showing illustrative examples.

scholarly journals Direct observation of backbone planarization via side-chain alignment in single bulky-substituted polythiophenes

2018 ◽  
Vol 115 (11) ◽  
pp. 2699-2704 ◽  
Author(s):  
Dominic Raithel ◽  
Lena Simine ◽  
Sebastian Pickel ◽  
Konstantin Schötz ◽  
Fabian Panzer ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Electronic Properties ◽  
Red Shift ◽  
Structural Motif ◽  
Side Chain ◽  
Side Chains ◽  
Single Chain ◽  
Optical And Electronic Properties ◽  
Backbone Conformation ◽  
The Impact

The backbone conformation of conjugated polymers affects, to a large extent, their optical and electronic properties. The usually flexible substituents provide solubility and influence the packing behavior of conjugated polymers in films or in bad solvents. However, the role of the side chains in determining and potentially controlling the backbone conformation, and thus the optical and electronic properties on the single polymer level, is currently under debate. Here, we investigate directly the impact of the side chains by studying the bulky-substituted poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) and the common poly(3-hexylthiophene) (P3HT), both with a defined molecular weight and high regioregularity, using low-temperature single-chain photoluminescence (PL) spectroscopy and quantum-classical simulations. Surprisingly, the optical transition energy of PDOPT is significantly (∼2,000 cm−1 or 0.25 eV) red-shifted relative to P3HT despite a higher static and dynamic disorder in the former. We ascribe this red shift to a side-chain induced backbone planarization in PDOPT, supported by temperature-dependent ensemble PL spectroscopy. Our atomistic simulations reveal that the bulkier 2,5-dioctylphenyl side chains of PDOPT adopt a clear secondary helical structural motif and thus protect conjugation, i.e., enforce backbone planarity, whereas, for P3HT, this is not the case. These different degrees of planarity in both thiophenes do not result in different conjugation lengths, which we found to be similar. It is rather the stronger electronic coupling between the repeating units in the more planar PDOPT which gives rise to the observed spectral red shift as well as to a reduced calculated electron−hole polarization.

Cryo-electron microscopy of two-dimensional crystals of reduced type B botulinum neurotoxin

1992 ◽  
Vol 50 (1) ◽  
pp. 530-531
Author(s):  
P. F. Flicker ◽  
V.S. Kulkarni ◽  
J. P. Robinson ◽  
G. Stubbs ◽  
B. R. DasGupta
Keyword(s):  
Disulfide Bonds ◽  
Clostridium Botulinum ◽  
Structural Changes ◽  
Two Dimensional ◽  
Type B ◽  
Single Chain ◽  
Muscle Paralysis ◽  
Cryo Electron Microscopy ◽  
Disulfide Linkages ◽  
Intracellular Action

Botulinum toxin is a potent neurotoxin produced by Clostridium botulinum. The toxin inhibits release of neurotransmitter, causing muscle paralysis. There are several serotypes, A to G, all of molecular weight about 150,000. The protein exists as a single chain or or as two chains, with two disulfide linkages. In a recent investigation on intracellular action of neurotoxins it was reported that type B neurotoxin can inhibit the release of Ca++-activated [3H] norepinephrine only if the disulfide bonds are reduced. In order to investigate possible structural changes in the toxin upon reduction of the disulfide bonds, we have prepared two-dimensional crystals of reduced type B neurotoxin. These two-dimensional crystals will be compared with those of the native (unreduced) type B toxin.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

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