Conductivity Of Polyacetylene Research Articles

A Brief Review on Fundamentals of Conductive Polymer (CPs)

Polymers are huge compounds made up of numerous monomers (repeatedsubunits). They have similar macro and micro properties, as well aselectrical transport qualities, semiconductive capabilities, and opticalfeatures. With the advent of conductive polyacetylene, conductivepolymers have gotten a lot of interest. These conductors have a wide rangeof electrical conductivity, which may be produced by doping, while beingmechanically flexible and having a high thermal stability. Polymers may becreated using a variety of methods, including chemical and electrochemicalpolymerization. With advancement in material stability and greaterproperty control, an increasing variety of new applications are now beinginvestigated.

Redox-Active Heteroatom-Functionalized Polyacetylenes.

The discovery of metallic conductivity in polyacetylene [-HC=CH-]n upon doping represents a landmark achievement. However, the insolubility of polyacetylene and a dearth of methods for its chemical modification have limited its widespread use. Here, we employ a ring-opening metathesis polymerization (ROMP) protocol to prepare functionalized polyacetylenes (fPAs) bearing: (1) electron-deficient boryl (-BR2 ) and phosphoryl (-P(O)R2 ) side chains; (2) electron-donating amino (-NR2 ) groups, and (3) ring-fused 1,2,3-triazolium units via strain-promoted Click chemistry. These functional groups render most of the fPAs soluble and can lead to intense light absorption across the visible to near-IR region. Also, the presence of redox-active boryl and amino groups leads to opposing near-IR optical responses upon (electro)chemical reduction or oxidation. Some of the resulting fPAs show greatly enhanced air stability when compared to known polyacetylenes. Lastly, these fPAs can be cross-linked to yield network materials with the full retention of optical properties.

Redox‐Active Heteroatom‐Functionalized Polyacetylenes

AbstractThe discovery of metallic conductivity in polyacetylene [‐HC=CH‐]n upon doping represents a landmark achievement. However, the insolubility of polyacetylene and a dearth of methods for its chemical modification have limited its widespread use. Here, we employ a ring‐opening metathesis polymerization (ROMP) protocol to prepare functionalized polyacetylenes (fPAs) bearing: (1) electron‐deficient boryl (‐BR2) and phosphoryl (‐P(O)R2) side chains; (2) electron‐donating amino (‐NR2) groups, and (3) ring‐fused 1,2,3‐triazolium units via strain‐promoted Click chemistry. These functional groups render most of the fPAs soluble and can lead to intense light absorption across the visible to near‐IR region. Also, the presence of redox‐active boryl and amino groups leads to opposing near‐IR optical responses upon (electro)chemical reduction or oxidation. Some of the resulting fPAs show greatly enhanced air stability when compared to known polyacetylenes. Lastly, these fPAs can be cross‐linked to yield network materials with the full retention of optical properties.

Polyacetylene Revisited: A Computational Study of the Molecular Engineering of N-type Polyacetylene.

The development of stable and highly conductive polymers, particularly n-type materials, remains an outstanding challenge in organic electronics. N-doped polyacetylene has long been studied as a highly conductive organic n-type material but suffers from extremely poor stability. Herein, we use DFT to model a series of n-doped polyacetylene derivatives, which have been functionalized with a range of electron-withdrawing substituents, with the goal of identifying attractive candidates for synthesis. We analyze the predicted molecular orbital energies, polymer planarity, and delocalization of charge carriers along the polymer backbone. In so doing, we develop key insights about the ideal substituents for both stable and highly conductive polyacetylene derivatives. This work will inform the modern synthesis and development of new polyacetylene derivatives. Beyond this, the work identifies a variety of new materials that have not yet been synthesized and should be good candidates for emerging optoelectronic applications including soft thermoelectrics, bioelectronics, and flexible device technologies.

A Water-Dispersible Quinoid-Resonant Conducting Polymer for Organic Electronics

Developing stable and solution-processable highly conductive polymers has been the research goal in organic electronics since the first demonstration of metallic conductive polyacetylene. Here, we used a unique quinoid-resonant building block thieno[3,4-b]thiophene (TbT) to develop a new water-dispersible conducting polymer, PTbT-Me:PSS. Linear polymerization and large surfactant counterion, poly(styrenesulfonate) (PSS−), were introduced, which enabled a high electrical conductivity of 68 S cm−1 and exhibited water-dispersible property. Interchain bipolaron was found in PTbT-Me:PSS when compared with polaron in PEDOT:PSS in their conducting mechanism. Moreover, we applied this highly conductive PTbT-Me:PSS as the solution-processed polymer thermoelectric material and a decent power factor of 3.1 μW m−1 K−2 was achieved.

Conducting Polymer Grafting: Recent and Key Developments.

Since the discovery of conductive polyacetylene, conductive electroactive polymers are at the focal point of technology generation and biocommunication materials. The reasons why this research never stops growing, are twofold: first, the demands from the advanced technology towards more sophistication, precision, durability, processability and cost-effectiveness; and second, the shaping of conducting polymer research in accordance with the above demand. One of the major challenges in conducting polymer research is addressing the processability issue without sacrificing the electroactive properties. Therefore, new synthetic designs and use of post-modification techniques become crucial than ever. This quest is not only advancing the field but also giving birth of new hybrid materials integrating merits of multiple functional motifs. The present review article is an attempt to discuss the recent progress in conducting polymer grafting, which is not entirely new, but relatively lesser developed area for this class of polymers to fine-tune their physicochemical properties. Apart from conventional covalent grafting techniques, non-covalent approach, which is relatively new but has worth creation potential, will also be discussed. The aim is to bring together novel molecular designs and strategies to stimulate the existing conducting polymer synthesis methodologies in order to enrich its fascinating chemistry dedicated toward real-life applications.

Conjugated polymers: From synthesis, transport properties, to device applications

Conjugated polymers: From synthesis, transport properties, to device applications

High-performance all-polymer dielectric and electrical energy storage materials containing conjugated segment and multi-fluorinated pendants

Highly polarizable block copolymer consisting of insulating polynorbornene and conductive polyacetylene segments with multi-fluorinated pendants was synthesized by tandem ring-opening metathesis polymerization and metathesis cyclopolymerization, which displayed relatively high dielectric constant of 8, very low dielectric loss of about 0.003, and enhanced energy density of 11.45 J cm−3 at the electric field strength of 450 MV m−1 accompanied with an excellent charge-discharge efficiency of 99%. The outstanding dielectric and energy storage capability were mainly attributed to high dipole moment of multi-fluorinated groups on polymer backbone and the interfacial polarization derived from the unique self-assembled nanostructure of block copolymers.

Disubstituted pendant-functionalized insulating-conductive block copolymer with enhanced dielectric and energy storage performance

Disubstituted pendant-functionalized block copolymer consisting of insulating polynorbornene and conductive polyacetylene segments was synthesized by tandem metathesis polymerization, and displayed high dielectric constant of 30 and low dielectric loss of about 0.04, while behaved bad film-forming property, which could be improved by incorporating polycyclooctene into polynorbornene backbone. The generated flexible block copolymer with well-defined nanostructure exhibited a relatively high dielectric constant of 23, very low dielectric loss of below 0.0035, and high stored and released energy densities up to 4.52 and 4.02 J cm−3 at the electric field of 165 MV m−1, respectively, accompanied with the charge-discharge efficiency of 90%. The enhanced dielectric and energy storage capability were attributed to high permanent dipole moment and the interfacial polarization derived from the unique nanomorphology of block copolymer.

50th Anniversary Perspective: Conducting/Semiconducting Conjugated Polymers. A Personal Perspective on the Past and the Future

It has been about 40 years since the field of organic conducting polymers was ignited by the demonstration of metallic conductivity in polyacetylene. A retrospective view of this research area suggests some areas remain ripe for discovery/innovation. The breadth of activities is too large to be comprehensive; hence, selected seminal, as well as some personal, contributions will be used to illustrate concepts and anecdotal ways to think about conducting polymer systems. This Perspective can serve as a tutorial for newcomers to the field and will also remind experts about results from the past. It begins with some history and simple views of electronic structure, with selected examples. Segmented polymers containing isolated redox units will be discussed as well as how these materials can be made to have high conductivity. Key examples illustrating the matching of redox potentials are transition metal hybrid structures. Interchain interactions are emphasized along with their role in determining the nature o...

Enhanced stability of conductive polyacetylene in ladder-like surface-grafted brushes

Formation and characterization of polyacetylene-based brushes that exhibit exceptional long term stability in air is presented here.

Vanishing conductivity of quantum solitons in polyacetylene

Quantum solitons or polarons are supposed to play a crucial role in the electric conductivity of polyacetylene, in the intermediate doping regime. We present an exact fully quantized calculation of the quantum soliton conductivity in polyacetylene and show that it vanishes exactly. This is obtained by applying a general method of soliton quantization, based on order–disorder duality, to a Z(2)-symmetric complex extension of the TLM dimerization effective field theory. We show that, in this theory, polyacetylene solitons are sine-Gordon solitons in the phase of the complex field.

Synthesis of Functionalized Asymmetric Star Polymers Containing Conductive Polyacetylene Segments by Living Anionic Polymerization

Novel 3-arm ABC, 4-arm ABCD, and 5-arm ABCDE asymmetric star polymers comprising the conductive polyacetylene precursor, poly(4-methylphenyl vinyl sulfoxide) (PMePVSO), and other segments, such as polystyrene, poly(alpha-methylstyrene), poly(4-methoxystyrene), poly(4-trimethylsilylstyrene), and poly(4-methylstyrene), were synthesized by the methodology based on living anionic polymerization using DPE-functionalized polymers. This methodology involves the addition reaction of a DPE-functionalized polymer to a living anionic polymer followed by the living anionic polymerization of MePVSO initiated from the in situ formed polymer anion with two, three, or four polymer segments. The resultant asymmetric star polymers possessed predetermined molecular weights, narrow molecular weight distributions (Mw/Mn < 1.03), and desired compositions as confirmed by SEC, 1H NMR, SLS, and elemental analysis. After thermal treatment, the PMePVSO segment in the star polymer could be completely converted into a conductive polyacetylene segment, evident from TGA and elemental analysis. These asymmetric star polymers are expected to exhibit interesting solution properties and unique microphase-separated morphological suprastructures with potential applications in nanoscopic conductive materials. Moreover, this methodology can afford the target asymmetric star polymers with arm segments varying in a wide range and enables the synthesis of more complex macromolecular architectures.

Influence of lattice fluctuations and coulomb interactions on the optical conductivity of polyacetylene

The optical conductivity of finite polyacetylene chains is calculated numerically, regarding the lattice fluctuations as static bond disorder and treating the electron-electron interaction in the Hartree-Fock approximation. In particular the role of excitons in polyacetylene is discussed.

Conductivity in polyacetylene. VI. Semiconductor?Metal transition of alkali-doped polymer

A local model is set up for the conductivity in alkali-doped polyacetylene (PA) based on results of ab initio and semiempirical calculations. At low doping levels, solitons and polarons appear naturally in the (nondegenerate) ground state. Alkali atoms donate their valence electrons to neutral solitons, which have the highest electron affinity in the PA structure. Due to the high polarizability of the PA chains, there is a charge buildup on a few carbon atoms close to the alkali ion. At the same time, a new soliton, screened from the alkali ion, is formed some distance away from the latter. This solition may migrate through the PA polymer partly by hopping for one chain segment to another (Ea ≥ 0.15 eV) and partly by soliton motion. In the calculation of the spectra, we used geometry-optimized structures and configuration interaction (i.e., taking into account electron-lattice interaction and explicit Coulomb correlation) and obtained good agreement with experimental spectra. As the concentration of alkali is increased, absorption occurs at energies below 1 eV. At higher doping levels, corresponding to a few mol%, the electrons delocalize over many alkali spacings and the trapping capability of the polymer decreases the conductivity becomes bandlike. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 655–665, 1997

Conductivity in polyacetylene. VI. Semiconductor—Metal transition of alkali‐doped polymer

Conductivity in polyacetylene. VI. Semiconductor—Metal transition of alkali‐doped polymer

Conductivity in polyacetylene. IV. Ab initio calculations for a two‐site model for electron transfer between allyl anion and allyl

Electron exchange between allyl molecules is studied using quantum chemical ab initio methods in order to model interchain electron transfer (ET) in polyacetylene. The reaction path, reorganization energy for ET (λ), and the electronic factor (Δ) are calculated using the UMP2, CASSCF, CASPT2, and CASSI methods. Changes in bond lengths are very small and their contribution to the internal reorganization energy almost negligible. Only changes in the bond angle leave significant contributions to the reorganization energy. The calculated potential energy surfaces can be represented as interacting parabolic-well potentials only in the case of CASSI. The UMP2, CASSCF, and CASPT2 methods give the localization of the electron even in the symmetric case and incorrect energy surfaces, with a cusp at the symmetry point. The electronic factor Δ is calculated using the two different methods, Koopmans' theorem and CASSI, with the same basis set. They are quantitatively very close for all intermolecular distances under study. However, Δ is sensitive to the basis set and cannot be calculated accurately in the present case. © 1997 John Wiley & Sons, Inc.

Conductivity in polyacetylene. IV. Ab initio calculations for a two-site model for electron transfer between allyl anion and allyl

Conductivity in polyacetylene. IV. Ab initio calculations for a two-site model for electron transfer between allyl anion and allyl

Conductivity in polyacetylene. II. Ab initio and tight-binding calculations of soliton structure and reorganization energy in ordered and disordered structures

Alkali-doped polyacetylene is considered as an electron-transfer system. To estimate the reorganization energy due to bond-length changes when electrons are added or subtracted, we applied the (U)MP2 and CASSCF methods to small systems of the type H(CH)NH. The simple tight-binding (Hückel) model with bond-length-dependent resonance integrals has been applied to the same and larger polyenes. The bond lengths are obtained via the bond orders for the various oxidation states. The results agree very well with the ab initio results and experiments for small polyenes. Odd-N and even-N systems behave differently. In odd-N systems, a structural “soliton” exists in the neutral molecule. An electron can be added or removed without bond-length change. In even-N chains, with perfect bond alternation in the neutral molecule, the bond length changes when an electron is accepted occur over about 20 carbon atoms. The reorganization energy tends to a constant value (0.22 eV) as the chain length is increased. Soliton structure is studied as a function of out-of-plane torsional defects and it is found that an additional electron is localized primarily on a segment with an odd number of carbon atoms. In the presence of positively charged ions, electrons are attracted toward this charge and positive solitons formed at some distance from the perturbing ion. © 1996 John Wiley & Sons, Inc.

Conductivity in polyacetylene. I. Ab initio calculation of charge localization, bond distances, and reorganization energy in model molecules

The electronic structure and geometry of neutral or charged molecules of the type trans-H(CH)nH is calculated using ab initio methods. The reorganization energy λ for adding or subtracting electrons is obtained for the cases with n=10, 11, and 12 using (U)MP2 with a 6-31G basis set. We find contributions to λ not only from C–C bond distance changes but also from C–C–C bond angle changes, whereas the contribution from C–H bond length and C–C–H bond angle changes are unimportant. The change of bond length when electrons are added to or subtracted from a neutral molecule with an even number of carbon atoms is typically 0.05–0.08 Å and occurs over a large part of the molecule, even if the donated charge is concentrated near the positive alkali ion. λ for one-electron reduction or oxidation is large in an even C chain but small in an odd C chain. The introduction of electronic correlation at (at least) the level of second-order Mo/ller–Plesset perturbation theory is important in the calculation of bond lengths and reorganization energies.