Hierarchically Structured Conjugated Polymers

2009 ◽  
Vol 1236 ◽  
Author(s):  
Holger Frauenrath
Keyword(s):  
Conjugated Polymers ◽  
Materials Science ◽  
Electronic Materials ◽  
Hierarchical Structures ◽  
Science Research ◽  
Building Blocks ◽  
Polymer Materials ◽  
Molecular Precursors ◽  
Quaternary Structures ◽  
Uniform Diameter

AbstractFunctional carbonaceous materials, organic electronic materials, and polymer materials which "speak the language" of biomaterials in their propensity for hierarchical structure formation play a central role in current materials science research. In this context, we prepared hierarchically structured conjugated polymers from diacetylene macromonomers based on β-sheet-forming oligopeptide-polymer conjugates as supramolecular building blocks. The monomers gave rise to supramolecular polymers with a finite number of strands, a uniform diameter of a few nanometers, and defined superstructures. These were then converted into conjugated polymers under retention of their hierarchical structures, leading to poly(diacetylene)s with multiple-helical quaternary structures and a rich folding behavior. The diacetylene macromonomers served as a model system to improve our understanding of how to use hydrogen-bonding sites in order to control the placement of reactive molecular precursors for hierarchically structured organic materials.

scholarly journals Solvent-Controlled Self-Assembled Oligopyrrolic Receptor

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1771
Author(s):  
Fei Wang ◽  
Kejiang Liang ◽  
Mads Christian Larsen ◽  
Steffen Bähring ◽  
Masatoshi Ishida ◽  
...  
Keyword(s):  
Materials Science ◽  
Science Research ◽  
Polymeric Chain ◽  
Supramolecular System ◽  
Receptor System ◽  
One Dimensional ◽  
X Ray ◽  
Host Guest Complex ◽  
Colorimetric Response ◽  
Strong Acids

We report a fully organic pyridine-tetrapyrrolic U-shaped acyclic receptor 10, which prefers a supramolecular pseudo-macrocyclic dimeric structure (10)2 in a less polar, non-coordinating solvent (e.g., CHCl3). Conversely, when it is crystalized from a polar, coordinating solvent (e.g., N,N-dimethylformamide, DMF), it exhibited an infinite supramolecular one-dimensional (1D) “zig-zag” polymeric chain, as inferred from the single-crystal X-ray structures. This supramolecular system acts as a potential receptor for strong acids, e.g., p-toluenesulfonic acid (PTSA), methane sulfonic acid (MSA), H2SO4, HNO3, and HCl, with a prominent colorimetric response from pale yellow to deep red. The receptor can easily be recovered from the organic solution of the host–guest complex by simple aqueous washing. It was observed that relatively stronger acids with pKa < −1.92 in water were able to interact with the receptor, as inferred from 1H NMR titration in tetrahydrofuran-d8 (THF-d8) and ultraviolet–visible (UV–vis) spectroscopic titrations in anhydrous THF at 298 K. Therefore, this new dynamic supramolecular receptor system may have potentiality in materials science research.

scholarly journals Synthesis of π-Conjugated Polymers Containing Benzotriazole Units via Palladium-Catalyzed Direct C-H Cross-Coupling Polycondensation for OLEDs Applications

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 254
Author(s):  
Dong Han ◽  
Jingwen Li ◽  
Qiang Zhang ◽  
Zewang He ◽  
Zhiwei Wu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Quantum Efficiency ◽  
Cross Coupling ◽  
Building Blocks ◽  
Gravimetric Analysis ◽  
19F Nmr Spectra ◽  
Light Emitting ◽  
Molecular Weights ◽  
Palladium Catalyzed ◽  
Red Luminescence

Four D-π-A conjugated polymers, namely P1–P4, which contain benzotriazole building blocks in their backbone as acceptor, are synthesized via palladium-catalyzed direct C-H cross-coupling polycondensation of 5,6-difluorobenzotriazole with different thiophene derivatives, including 3-octylthiophene, 2,2’-bithiophene, thieno[3,4-b][1,4]dioxine, and 4,4-dioctyl-4H-silolo-[3,2-b:4,5-b’]dithiophene as donor units, respectively. Taking the polymer P1 as an example, the chemical structure of the polymer is demonstrated by 1H and 19F NMR spectra. The optical, electrochemical, and thermal properties of these polymers are assessed by UV–vis absorption and fluorescence spectroscopy, cyclic voltammetry (CV), and thermal gravimetric analysis (TGA), respectively. DFT simulations of all polymers are also performed to understand their physicochemical properties. Furthermore, P1 and P2, which have relatively higher molecular weights and better fluorescent quantum efficiency than those of P3 and P4, are utilized as lighting emitters for organic light-emitting diodes (OLEDs), affording promising green and red luminescence with 0.07% and 0.14% of maximum external quantum efficiency, respectively, based on a device with an architecture of ITO/PEDOT:PSS/PTAA/the polymer emitting layer/TPBi/LiF/Al.

DNA-based self-assembly of nanostructures

2017 ◽  
Author(s):  
Joshua D. Carter ◽  
Chenxiang Lin ◽  
Yan Liu ◽  
Hao Yan ◽  
Thomas H. LaBean
Keyword(s):  
Self Assembly ◽  
Materials Science ◽  
Directed Assembly ◽  
Building Blocks ◽  
Hierarchical Assembly ◽  
Synthetic Dna ◽  
Nanoscale Manufacturing ◽  
Covalently Linked ◽  
Design Construction ◽  
Proteins And Peptides

This article examines the DNA-based self-assembly of nanostructures. It first reviews the development of DNA self-assembly and DNA-directed assembly, focusing on the main strategies and building blocks available in the modern molecular construction toolbox, including the design, construction, and analysis of nanostructures composed entirely of synthetic DNA, as well as origami nanostructures formed from a mixture of synthetic and biological DNA. In particular, it considers the stepwise covalent synthesis of DNA nanomaterials, unmediated assembly of DNA nanomaterials, hierarchical assembly, nucleated assembly, and algorithmic assembly. It then discusses DNA-directed assembly of heteromaterials such as proteins and peptides, gold nanoparticles, and multicomponent nanostructures. It also describes the use of complementary DNA cohesion as 'smart glue' for bringing together covalently linked functional groups, biomolecules, and nanomaterials. Finally, it evaluates the potential future of DNA-based self-assembly for nanoscale manufacturing for applications in medicine, electronics, photonics, and materials science.

Conjugated Polymer Surfaces and Interfaces for Light-Emitting Devices

MRS Bulletin ◽  
1997 ◽  
Vol 22 (6) ◽  
pp. 46-51 ◽  
Author(s):  
W.R. Salaneck ◽  
J.L. Brédas
Keyword(s):  
Conjugated Polymers ◽  
Photoelectron Spectroscopy ◽  
Electronic Materials ◽  
Structural Information ◽  
Molecular Solids ◽  
Chemical Modeling ◽  
Polymer Leds ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Surfaces And Interfaces

Since the discovery of high electrical conductivity in doped polyacetylene in 1977, π-conjugated polymers have emerged as viable semiconducting electronic materials for numerous applications. In the context of polymer electronic devices, one must understand the nature of the polymer surface's electronic structure and the interface with metals. For conjugated polymers, photoelectron spectroscopy—especially in connection with quantum-chemical modeling—provides a maximum amount of both chemical and electronic structural information in one (type of) measurement. Some details of the early stages of interface formation with metals on the surfaces of conjugated polymers and model molecular solids in connection with polymer-based light-emitting devices (LEDs) are outlined. Then a chosen set of issues is summarized in a band structure diagram for a polymer LED, based upon a “clean calcium electrode” on the clean surface of a thin film of poly(p-phenylene vinylene) (PPV). This diagram helps to point out the complexity of the systems involved in polymer LEDs. No such thing as “an ideal metal-on-polymer contact” exists. There is always some chemistry occurring at the interface.

High-Impact Practices in Materials Science Education: Student Research Internships Leading to Pedagogical Innovation in STEM Laboratory Learning Activities

MRS Advances ◽  
2017 ◽  
Vol 2 (31-32) ◽  
pp. 1667-1672 ◽  
Author(s):  
Lon A. Porter
Keyword(s):  
Computer Aided Design ◽  
Materials Science ◽  
Undergraduate Research ◽  
Science Research ◽  
High Impact ◽  
Digital Design ◽  
Education Student ◽  
Research Experience ◽  
Student Research ◽  
Pedagogical Innovation

ABSTRACTTraditional lecture-centered approaches alone are inadequate for preparing students for the challenges of creative problem solving in the STEM disciplines. As an alternative, learnercentered and other high-impact pedagogies are gaining prominence. The Wabash College 3D Printing and Fabrication Center (3D-PFC) supports several initiatives on campus, but one of the most successful is a computer-aided design (CAD) and fabrication-based undergraduate research internship program. The first cohort of four students participated in an eight-week program during the summer of 2015. A second group of the four students was successfully recruited to participate the following summer. This intensive materials science research experience challenged students to employ digital design and fabrication in the design, testing, and construction of inexpensive scientific instrumentation for use in introductory STEM courses at Wabash College. The student research interns ultimately produced a variety of successful new designs that could be produced for less than $25 per device and successfully detect analytes of interest down to concentrations in the parts per million (ppm) range. These student-produced instruments have enabled innovations in the way introductory instrumental analysis is taught on campus. Beyond summer work, the 3D-PFC staffed student interns during the academic year, where they collaborated on various cross-disciplinary projects with students and faculty from departments such as mathematics, physics, biology, rhetoric, history, classics, and English. Thus far, the student work has led to three campus presentations, four presentations at national professional conferences, and three peer-reviewed publications. The following report highlights initial progress as well as preliminary assessment findings.

Zeolates: A Coordination Chemistry View of Metal-Ligand Bonding in Intrazeolite MOCVD Type Precursors and Semiconductor Nanoclusters

1992 ◽  
Vol 277 ◽  
Author(s):  
Geoffrey A. Ozin ◽  
Carol L. Bowes ◽  
Mark R. Steele
Keyword(s):  
Self Assembly ◽  
Materials Science ◽  
Zeolite Y ◽  
Chemical Vapour ◽  
Internal Surface ◽  
Building Blocks ◽  
Structural Features ◽  
Organic Chemical ◽  
Wide Range ◽  
Shape Selective

ABSTRACTVarious MOCVD (metal-organic chemical vapour deposition) type precursors and their self-assembled semiconductor nanocluster products [1] have been investigated in zeolite Y hosts. From analysis of in situ observations (FTIR, UV-vis reflectance, Mössbauer, MAS-NMR) of the reaction sequences and structural features of the precursors and products (EXAFS and Rietveld refinement of powder XRD data) the zeolite is viewed as providing a macrospheroidal, multidendate coordination environment towards encapsulated guests. By thinking about the α- and β-cages of the zeolite Y host effectively as a zeolate ligand composed of interconnected aluminosilicate “crown ether-like” building blocks, the materials chemist is able to better understand and exploit the reactivity and coordination properties of the zeolite internal surface for the anchoring and self-assembly of a wide range of encapsulated guests. This approach helps with the design of synthetic strategies for creating novel guest-host inclusion compounds having possible applications in areas of materials science such as nonlinear optics, quantum electronics, and size/shape selective catalysis.

Accommodating Different Learning Styles Using e.g., “Flash Movies” in an Introductory Course on Materials Science.

2004 ◽  
Vol 861 ◽  
Author(s):  
I. R. Harrison ◽  
P. C. Ray ◽  
M. Fleck ◽  
R. H. Locklin ◽  
A. Weisner ◽  
...  
Keyword(s):  
Learning Styles ◽  
Materials Science ◽  
Electronic Materials ◽  
Learning Objects ◽  
Ease Of Use ◽  
Hard Copy ◽  
Introductory Course ◽  
On Line ◽  
Power Point ◽  
Subject Material

ABSTRACTIn addition to a hard-copy textbook, Power-Point presentations and videos, the authors have developed a series of Flash modules and on-line quizzing tools for use in teaching and assessing the fundamentals of Materials Science and Engineering. The original thrust was aimed at non-science majors at university, but the modules are also designed for ease of use in high school curricula. In the current paper, we present our philosophy for the presentation of materials' related subject material, using different learning objects, by describing one particular module: on electronic materials.

O,O′-DisubstitutedN,N′-Dihydroxynaphthalenediimides (DHNDI): First Principles Designed Organic Building Blocks for Materials Science

2011 ◽  
Vol 13 (20) ◽  
pp. 5432-5435 ◽  
Author(s):  
Eric Assen B. Kantchev ◽  
Huei Shuan Tan ◽  
Tyler B. Norsten ◽  
Michael B. Sullivan
Keyword(s):  
First Principles ◽  
Materials Science ◽  
Building Blocks
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