π-Stacked Polymers

A special issue of Polymers (ISSN 2073-4360).

Deadline for manuscript submissions: closed (31 May 2018) | Viewed by 50503

Special Issue Editor


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Guest Editor
Institute for Catalysis and Graduate School of Chemical Sciences and Engineering, Hokkaido University, N21 W10, Kita-ku, Sapporo 001-0021, Japan
Interests: side-chain π-electronic polymers; main-chain π-conjugated polymers; chirality, controlled polymerization; π-electronic supramolecular systems

Special Issue Information

Dear Colleagues,

This Special Issue focuses on the synthesis, structure and properties/functions of polymers and molecular systems having π-electron systems with controlled spatial arrangements. Of particular interest are those with intra-chain and inter-chain π-stacked structures. π-Electronic polymer and molecular systems exhibit photo electronic properties such as conduction, emission, optical non-linearity, and even photo catalytic activity. These properties and functions are based on mobility of charges and/or energy transfer through a chain and/or between chains. It is hence important to design a polymer or a molecular system where π-electronic systems having tailored alignments such as π-stacking.

Papers are sought that discuss the latest research in the area or summarize selected areas of the field. The scope of the Special Issue encompasses the studies on the synthesis, structure, properties, and theories of intra-chain π-stacked polymers, inter-chain π-stacked systems comprising of conjugated and non-conjugated π-electronic polymers, and also those of supramolecules comprising of stacked π-electronic species.  Further, novel forms of accumulation of π-electronic systems other than π-stacking will be covered.

Prof. Dr. Tamaki Nakano
Guest Editor

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Keywords

  • π-Stacked polymers
  • π-Conjugated polymers
  • Chiral polymers
  • Conducting polymers
  • Light-emitting polymers
  • Macromolecular catalysis
  • Supramolecules and molecular assemblies consisting of accumulated π-electron systems

Published Papers (10 papers)

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Research

10 pages, 2126 KiB  
Communication
π-Stacked Polymer Consisting of a Pseudo–meta–[2.2]Paracyclophane Skeleton
by Hazuki Maeda, Mayu Kameda, Takuji Hatakeyama and Yasuhiro Morisaki
Polymers 2018, 10(10), 1140; https://doi.org/10.3390/polym10101140 - 12 Oct 2018
Cited by 9 | Viewed by 4396
Abstract
A novel π-stacked polymer based on a pseudo–meta–linked [2.2]paracyclophane moieties was synthesized by Sonogashira-Hagihara coupling. The UV-vis absorption spectra of the synthesized polymer and model compounds revealed an extension of the conjugation length owing to the through-space conjugation. The optical properties [...] Read more.
A novel π-stacked polymer based on a pseudo–meta–linked [2.2]paracyclophane moieties was synthesized by Sonogashira-Hagihara coupling. The UV-vis absorption spectra of the synthesized polymer and model compounds revealed an extension of the conjugation length owing to the through-space conjugation. The optical properties of the π-stacked dimer with the pseudo–meta–linked [2.2]paracyclophane unit were compared with those of the corresponding dimers with the pseudo–ortho– and pseudo–para–linked [2.2]paracyclophane units. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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20 pages, 4751 KiB  
Article
Structural Manipulation of the Conjugated Phenyl Moiety in 3-Phenylbenzofulvene Monomers: Effects on Spontaneous Polymerization
by Marco Paolino, Giorgio Grisci, Annalisa Reale, Vincenzo Razzano, Germano Giuliani, Alessandro Donati, Raniero Mendichi, Daniele Piovani, Antonella C. Boccia, Alessandro Grillo, Gianluca Giorgi and Andrea Cappelli
Polymers 2018, 10(7), 752; https://doi.org/10.3390/polym10070752 - 07 Jul 2018
Cited by 14 | Viewed by 7019
Abstract
Spontaneous polymerization is an intriguing phenomenon in which pure monomers begin their polymerization without initiators or catalysts. Previously, 3-phenylbenzofulvene monomers were found to polymerize spontaneously after solvent removal. Here, eight new 3-substituted benzofulvene monomers 1a–h were synthesized in order to investigate the effects [...] Read more.
Spontaneous polymerization is an intriguing phenomenon in which pure monomers begin their polymerization without initiators or catalysts. Previously, 3-phenylbenzofulvene monomers were found to polymerize spontaneously after solvent removal. Here, eight new 3-substituted benzofulvene monomers 1a–h were synthesized in order to investigate the effects of differently substituted aromatic rings in position 3 of the benzofulvene scaffold on spontaneous polymerization. The newly synthesized monomers maintained the tendency toward spontaneous polymerization. However, monomer 1a, bearing an ortho-methoxy substituted phenyl, polymerized hardly, thus producing low polymerization yields, inhomogeneous structure, and low molecular weight of the obtained polymeric material. This result suggested the importance of the presence of hydrogen atoms in the 2′-position to achieve productive interactions among the monomers in the recognition step preluding the spontaneous polymerization and among the monomeric units in the polybenzofulvene backbones. Moreover, this study paves the way to modify the pendant rings in position 3 of the indene scaffold to synthesize new polybenzofulvene derivatives variously decorated. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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12 pages, 2497 KiB  
Article
Synthesis and Optoelectronic Properties of Block and Random Copolymers Containing Pendant Carbazole and (Di)phenylanthracene
by Chen-Tsyr Lo, Yohei Abiko, Jun Kosai, Yuichiro Watanabe, Kazuhiro Nakabayashi and Hideharu Mori
Polymers 2018, 10(7), 721; https://doi.org/10.3390/polym10070721 - 01 Jul 2018
Cited by 7 | Viewed by 3340
Abstract
Synthesis of novel block and random copolymers, containing a carbazole unit and (di)phenylanthracene moiety in the side chains, has been described in this paper. Block and random copolymers composed of 4-bromophenyl vinyl sulfide (BPVS) and N-vinylcarbazole (NVC) were initially prepared by reversible [...] Read more.
Synthesis of novel block and random copolymers, containing a carbazole unit and (di)phenylanthracene moiety in the side chains, has been described in this paper. Block and random copolymers composed of 4-bromophenyl vinyl sulfide (BPVS) and N-vinylcarbazole (NVC) were initially prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. Then, anthracene-based groups were introduced on the bromophenyl unit in the carbazole-containing copolymers by Pd-catalyzed coupling to yield functional copolymers with additional (di)phenylanthracene units. The resulting copolymers, having two distinct electronic functionalities, exhibited characteristic fluorescence resonance energy transfer, as confirmed by UV-vis and fluorescence spectra. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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11 pages, 3088 KiB  
Article
Synthesis of Amphiphilic Block Copolymers Containing Chiral Polythiophene Chains and Their Micelle Formation and Chiroptical Properties
by Daisuke Hirose, Satoru Nozaki, Shigeyoshi Kanoh and Katsuhiro Maeda
Polymers 2018, 10(7), 718; https://doi.org/10.3390/polym10070718 - 30 Jun 2018
Cited by 3 | Viewed by 4829
Abstract
Amphiphilic block copolymers consisting of hydrophobic regioregular head-to-tail (HT) chiral ((S)-poly-1a-b-poly-3) or achiral (poly-1b-b-poly-3) polythiophene chains and a hydrophilic poly(acrylic acid) chain were synthesized. (S)-Poly-1a- [...] Read more.
Amphiphilic block copolymers consisting of hydrophobic regioregular head-to-tail (HT) chiral ((S)-poly-1a-b-poly-3) or achiral (poly-1b-b-poly-3) polythiophene chains and a hydrophilic poly(acrylic acid) chain were synthesized. (S)-Poly-1a-b-poly-3 with a chiral polythiophene block formed a micelle in water that exhibited a characteristic induced circular dichroism (ICD) in the π–π* transition region due to the formation of supramolecular π-stacked chiral aggregates of the chiral polythiophene blocks in the core. These aggregates were stable, showing no precipitation for more than 5 days. Micelles consisting of chiral (S)-poly-1a-b-poly-3 and achiral poly-1b-b-poly-3 showed negative nonlinear effects on supramolecular chiral aggregate formation in the core. Chiral polythiophene aggregates formed in (S)-poly-1a-b-poly-3 micelle cores were stabilized by the crosslinking of poly(acrylic acid) blocks with diamines in the shell. The ICD intensity of the (S)-poly-1a-b-poly-3 micelle after shell crosslinking showed almost no change with temperature, while that before shell crosslinking decreased with increasing temperature. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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14 pages, 2196 KiB  
Article
Free-Radical Copolymerization of Dibenzofulvene with (Meth)acrylates Leading to π-Stacked Copolymers
by Jiyue Luo, Yue Wang and Tamaki Nakano
Polymers 2018, 10(6), 654; https://doi.org/10.3390/polym10060654 - 11 Jun 2018
Cited by 5 | Viewed by 4980
Abstract
Copolymerizations of dibenzofulvene (DBF) with methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), methyl acrylate (MA), and 2-hydroxyethyl acrylate (HEA) were conducted under free radical conditions in toluene using α,α′-azobisisobutylonitrile (AIBN) as the initiator. In the copolymerizations, DBF indicated much higher reactivity than the comonomers, [...] Read more.
Copolymerizations of dibenzofulvene (DBF) with methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), methyl acrylate (MA), and 2-hydroxyethyl acrylate (HEA) were conducted under free radical conditions in toluene using α,α′-azobisisobutylonitrile (AIBN) as the initiator. In the copolymerizations, DBF indicated much higher reactivity than the comonomers, and the products comprised mainly of DBF units. NMR, UV, and fluorescence spectra, as well as electrochemical features indicated that the copolymers possess both isolated and rather short, sequential (meth)acrylate units, as well as π-stacked and unstacked DBF sequences. Isolated (meth)acrylate units are proposed to be sandwiched between DBF units. The ratios of π-stacked and unstacked side-chain fluorene groups of DBF units in excited states were accurately determined on the basis of fluorescent emission spectra; DBF units are mostly π-stacked in excited states as disclosed by fluorescence spectra. Two types of π-stacked sequences were suggested to be present in the ground state by electrochemical analysis. The copolymers exhibited higher solubility than pure poly(DBF). Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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11 pages, 1631 KiB  
Article
Chirality Construction from Preferred π-π Stacks of Achiral Azobenzene Units in Polymer: Chiral Induction, Transfer and Memory
by Tengfei Miao, Lu Yin, Xiaoxiao Cheng, Yin Zhao, Wenjie Hou, Wei Zhang and Xiulin Zhu
Polymers 2018, 10(6), 612; https://doi.org/10.3390/polym10060612 - 04 Jun 2018
Cited by 22 | Viewed by 4583
Abstract
The induction of supramolecular chirality from achiral polymers has been widely investigated in composite systems consisting of a chiral guest, achiral host, and solvents. To further study and understand the process of chirality transfer from a chiral solvent or chiral molecules to an [...] Read more.
The induction of supramolecular chirality from achiral polymers has been widely investigated in composite systems consisting of a chiral guest, achiral host, and solvents. To further study and understand the process of chirality transfer from a chiral solvent or chiral molecules to an achiral polymer backbone or side-chain units, an alternative is to reduce the components in the supramolecular assembled systems. Herein, achiral side-chain azobenzene (Azo)-containing polymers, poly(6-[4-(4-methoxyphenylazo) phenoxy] hexyl methacrylate) (PAzoMA), with different Mns, were synthesized by atom transfer radical polymerization (ATRP). Preferred chirality from supramolecular assembled trans-Azo units of PAzoMAs is successfully induced solely by the neat limonene. These aggregates of the polymers in limonene solution were characterized by circular dichroism (CD), UV-vis spectra, and dynamic light scattering (DLS) under different temperatures. The temperature plays an important role in the course of chiral induction. Meanwhile, supramolecular chirality can be constructed in the solid films of the achiral side-chain Azo-containing polymers that were triggered by limonene vapors. Also, it can be erased after heated above the glass transition temperature (Tg) of the polymer, and recovered after cooling down in the limonene vapors. A chiroptical switch can be built by alternately changing the temperature. The solid films show good chiral memory behaviors. The current results will facilitate studying the mechanism of chirality transfer induced by chiral solvent and improve potential application possibilities in chiral film materials. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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11 pages, 2684 KiB  
Article
Highly Graphitized Carbon Coating on SiO with a π–π Stacking Precursor Polymer for High Performance Lithium-Ion Batteries
by Shan Fang, Ning Li, Tianyue Zheng, Yanbao Fu, Xiangyun Song, Ting Zhang, Shaopeng Li, Bin Wang, Xiaogang Zhang and Gao Liu
Polymers 2018, 10(6), 610; https://doi.org/10.3390/polym10060610 - 04 Jun 2018
Cited by 14 | Viewed by 5827
Abstract
A highly graphitized carbon on a silicon monoxide (SiO) surface coating at low temperature, based on polymer precursor π–π stacking, was developed. A novel conductive and electrochemically stable carbon coating was rationally designed to modify the SiO anode materials by controlling the sintering [...] Read more.
A highly graphitized carbon on a silicon monoxide (SiO) surface coating at low temperature, based on polymer precursor π–π stacking, was developed. A novel conductive and electrochemically stable carbon coating was rationally designed to modify the SiO anode materials by controlling the sintering of a conductive polymer, a pyrene-based homopolymer poly (1-pyrenemethyl methacrylate; PPy), which achieved high graphitization of the carbon layers at a low temperature and avoided silicon carbide formation and possible SiO material transformation. When evaluated as the anode of a lithium-ion battery (LIB), the carbon-coated SiO composite delivered a high discharge capacity of 2058.6 mAh/g at 0.05 C of the first formation cycle with an initial Coulombic efficiency (ICE) of 62.2%. After 50 cycles at 0.1 C, this electrode capacity was 1090.2 mAh/g (~82% capacity retention, relative to the capacity of the second cycle at 0.1 °C rate), and a specific capacity of 514.7 mAh/g was attained at 0.3 C after 500 cycles. Furthermore, the coin-type full cell composed of the carbon coated SiO composite anode and the Li[Ni0.5Co0.2Mn0.3O2] cathode attained excellent cycling performance. The results show the potential applications for using a π–π stacking polymer precursor to generate a highly graphitize coating for next-generation high-energy-density LIBs. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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14 pages, 2568 KiB  
Article
The Effect of Aromatic Diimide Side Groups on the π-Conjugated Polymer Properties
by Anna Drewniak, Mateusz D. Tomczyk, Lukasz Hanusek, Anna Mielanczyk, Krzysztof Walczak, Pawel Nitschke, Barbara Hajduk and Przemyslaw Ledwon
Polymers 2018, 10(5), 487; https://doi.org/10.3390/polym10050487 - 01 May 2018
Cited by 10 | Viewed by 5039
Abstract
The presented study describes the method for the synthesis and characterization of a new class of conjugated copolymers containing a perylenediimide (PDI) and naphthalene diimide (NDI) side groups. The main conjugated backbone is a donor-acceptor polymer poly[3,6-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] containing thiophene and carbazole [...] Read more.
The presented study describes the method for the synthesis and characterization of a new class of conjugated copolymers containing a perylenediimide (PDI) and naphthalene diimide (NDI) side groups. The main conjugated backbone is a donor-acceptor polymer poly[3,6-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] containing thiophene and carbazole as donor units and benzothiadiazole as an acceptor unit. The presented compounds were synthesized in a multistep synthesis. The polymerization was carried out by Suzuki or Stille coupling reaction. Redox properties of the studied polymers were tested in different conditions. Electrochemical investigation revealed independent reduction of the main polymer chain and diimide side groups. UV-Vis spectroscopy revealed the overlap of two absorption spectra. The difference between the electron affinity of the polymer main chain and that of the diimides estimated electrochemically is approximately 0.3 eV. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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16 pages, 16703 KiB  
Article
Donor-Acceptor-Type Copolymers Based on 3,4-Propylenedioxy-thiophene and 5,6-Difluorobenzotriazole: Synthesis and Electrochromic Properties
by Fanda Feng, Lingqian Kong, Hongmei Du, Jinsheng Zhao and Junhong Zhang
Polymers 2018, 10(4), 427; https://doi.org/10.3390/polym10040427 - 11 Apr 2018
Cited by 15 | Viewed by 4130
Abstract
Three solution-processable D-A-type conjugated polymers P1, P2 and P3 were successfully synthesized via the Pd-catalyzed Stille cross-coupling copolymerization approach, with 6,8-Dibromo-3,3-bis-decyl-3,4-dihydro-2H-thieno[3,4-b][1,4] dioxepine (M1) and 2,5-Bis(trimethylstannanyl)thiophene (M3) as the donor units and 4,7-Dibromo-5,6-difluoro-2-(2-hexyl-decyl)-2H-benzotriazole (M2) as the acceptor [...] Read more.
Three solution-processable D-A-type conjugated polymers P1, P2 and P3 were successfully synthesized via the Pd-catalyzed Stille cross-coupling copolymerization approach, with 6,8-Dibromo-3,3-bis-decyl-3,4-dihydro-2H-thieno[3,4-b][1,4] dioxepine (M1) and 2,5-Bis(trimethylstannanyl)thiophene (M3) as the donor units and 4,7-Dibromo-5,6-difluoro-2-(2-hexyl-decyl)-2H-benzotriazole (M2) as the acceptor unit, wherein the feed ratio of the three units was 1:3:4 (M1:M2:M3, the same below), 1:1:2 and 3:1:4 for P1, P2, and P3, respectively. The results obtained by our test showed that the feed ratio between the D and A units had a significant effect on both the electrochemical and the spectroelectrochemical properties of the three polymers. The copolymers exhibited a gradually deepening red color in neutral state with the increase of M1 content and then turned to a transmissive grey color in the oxidation state. Also, three copolymers showed good performance in electrochromic parameters, which mainly consists of optical contrast, response time, and coloration efficiency. In general, the excellent electrochromic performances of the copolymers make them outstanding candidates for electrochromic material applications. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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16 pages, 3698 KiB  
Article
Thickening Supercritical CO2 with π-Stacked Co-Polymers: Molecular Insights into the Role of Intermolecular Interaction
by Wenchao Sun, Baojiang Sun, Ying Li, Xiaonan Huang, Haiming Fan, Xinxin Zhao, Haoyang Sun and Wenxia Sun
Polymers 2018, 10(3), 268; https://doi.org/10.3390/polym10030268 - 06 Mar 2018
Cited by 22 | Viewed by 5117
Abstract
Vinyl Benzoate/Heptadecafluorodecyl acrylate (VBe/HFDA) co-polymers were synthesized and characterized as thickening agents for supercritical carbon dioxide (SC-CO2). The solubility and thickening capability of the co-polymer samples in SC-CO2 were evaluated by measuring cloud point pressure and relative viscosity. The molecular [...] Read more.
Vinyl Benzoate/Heptadecafluorodecyl acrylate (VBe/HFDA) co-polymers were synthesized and characterized as thickening agents for supercritical carbon dioxide (SC-CO2). The solubility and thickening capability of the co-polymer samples in SC-CO2 were evaluated by measuring cloud point pressure and relative viscosity. The molecular dynamics (MD) simulation for all atoms was employed to simulate the microscopic molecular behavior and the intermolecular interaction of co-polymer–CO2 systems. We found that the introduction of VBe group decreased the polymer–CO2 interaction and increased the polymer–polymer interaction, leading to a reduction in solubility of the co-polymers in SC-CO2. However, the co-polymer could generate more effective inter-chain interaction and generate more viscosity enhancement compared to the Poly(Heptadecafluorodecyl) (PHFDA) homopolymer due to the driving force provided by π-π stacking of the VBe groups. The optimum molar ratio value for VBe in co-polymers for the viscosity enhancement of SC-CO2 was found to be 0.33 in this work. The P(HFDA0.67-co-VBe0.33) was able to enhance the viscosity of SC-CO2 by 438 times at 5 wt. %. Less VBe content would result in a lack of intermolecular interaction, although excessive VBe content would generate more intramolecular π-π stacking and less intermolecular π-π stacking. Both conditions reduce the thickening capability of the P(HFDA-co-VBe) co-polymer. This work presented the relationship between structure and performance of the co-polymers in SC-CO2 by combining experiment and molecular simulations. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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