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Open AccessArticle

Photoluminescence Quenching of a Novel Electroconductive Poly(propylene thiophenoimine)-co-Poly(ethylenedioxy thiophene) Star Copolymer

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Anne Lutgarde Djoumessi Yonkeu

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Miranda Mengwi Ndipingwi

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Polymers 2020, 12(12), 2894; https://doi.org/10.3390/polym12122894 - 03 Dec 2020

Cited by 3 | Viewed by 1605

Abstract

A generation 1 poly(propylene thiophenoimine)-co-poly(ethylenedioxy thiophene) (G1PPT-co-PEDOT) star copolymer, which exhibits a strong optical absorption over a broad range in the ultraviolet–visible (UV-Vis) region and with good electro/conductive properties, was chemically prepared for the first time. Synthesis of the star copolymer, G1PPT-co-PEDOT was [...] Read more.

A generation 1 poly(propylene thiophenoimine)-co-poly(ethylenedioxy thiophene) (G1PPT-co-PEDOT) star copolymer, which exhibits a strong optical absorption over a broad range in the ultraviolet–visible (UV-Vis) region and with good electro/conductive properties, was chemically prepared for the first time. Synthesis of the star copolymer, G1PPT-co-PEDOT was confirmed by spectroscopic studies. Indeed, the disappearance of the very high intensity bands, C–H bending at α-position (687 cm⁻¹), and C=N stretching (1620 cm⁻¹) in the Fourier transform infrared spectroscopy (FTIR) of G1PPT-co-PEDOT, which were initially present in the spectrum of the thiolated starting material, G1PPT, confirmed copolymerization. Furthermore, a large bathochromic shift in the onset wavelength of the UV-Vis absorbance spectra from 367 nm in G1PPT to 674 nm in G1PPT-co-PEDOT further attests of successful copolymerization. The electrochemical analysis of G1PPT-co-PEDOT achieved a highest occupied molecular orbital (HOMO) energy level value of 5.3 eV, which is reminiscent of the value for an ideal electron-donor material. Photoluminescence quenching of up to 82% was observed in solution blends of the G1PPT-co-PEDOT star copolymer and N,N′-diisopropyl naphthalene diimide (NDI). This demonstrates the occurrence of photoinduced intermolecular charge transfer (PICT) from the electron-donating G1PPT-co-PEDOT to the electron accepting NDI, a good property, beneficial for optoelectronic and photovoltaic applications. Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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Open AccessArticle

The Study of the Degree of Crystallinity, Electrical Equivalent Circuit, and Dielectric Properties of Polyvinyl Alcohol (PVA)-Based Biopolymer Electrolytes

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Polymers 2020, 12(10), 2184; https://doi.org/10.3390/polym12102184 - 24 Sep 2020

Cited by 57 | Viewed by 3121

Abstract

This report presents a facile and efficient methodology for the fabrication of plasticized polyvinyl alcohol (PVA):chitosan (CS) polymer electrolytes using a solution cast technique. Regarding characterizations of electrical properties and structural behavior, the electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) are used, [...] Read more.

This report presents a facile and efficient methodology for the fabrication of plasticized polyvinyl alcohol (PVA):chitosan (CS) polymer electrolytes using a solution cast technique. Regarding characterizations of electrical properties and structural behavior, the electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) are used, respectively. Crystalline peaks appear in the XRD pattern of the PVA:CS:NH₄I while no peaks can be seen in the XRD pattern of plasticized systems. The degree of crystallinity is calculated for all the samples from the deconvoluted area of crystalline and amorphous phases. Considering the EIS measurements, the most conductive plasticized system shows a relatively high conductivity of (1.37 × 10⁻⁴) S/cm, which is eligible for applications in energy storage devices. The analysis of the EIS spectra reveals a decrease in bulk resistance which indicates an increase in free ion carriers. The electrical equivalent circuit (EEC) model is used in the analysis of EIS plots. Dielectric properties are modified with the addition of glycerol as a plasticizer. It is proved that the addition of glycerol as a plasticizer lowers ion association. It also shows, at the low-frequency region, a large value of a dielectric constant which is correlated with electrode polarization (EP). The distribution of relaxation times is associated with conducting ions. Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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Open AccessArticle

The Study of EDLC Device with High Electrochemical Performance Fabricated from Proton Ion Conducting PVA-Based Polymer Composite Electrolytes Plasticized with Glycerol

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Polymers 2020, 12(9), 1896; https://doi.org/10.3390/polym12091896 - 23 Aug 2020

Cited by 24 | Viewed by 2710

Abstract

In the present work, a novel polymer composite electrolytes (PCEs) based on poly(vinyl alcohol) (PVA): ammonium thiocyanate (NH₄SCN): Cd(II)-complex plasticized with glycerol (Gly) are prepared by solution cast technique. The film structure was examined by XRD and FTIR routes. The utmost [...] Read more.

In the present work, a novel polymer composite electrolytes (PCEs) based on poly(vinyl alcohol) (PVA): ammonium thiocyanate (NH₄SCN): Cd(II)-complex plasticized with glycerol (Gly) are prepared by solution cast technique. The film structure was examined by XRD and FTIR routes. The utmost ambient temperature DC ionic conductivity (σ_DC) of 2.01 × 10⁻³ S cm⁻¹ is achieved. The film morphology was studied by field emission scanning electron microscopy (FESEM). The trend of σ_DC is further confirmed with investigation of dielectric properties. Transference numbers of ions (t_ion) and electrons (t_el) are specified to be 0.96 and 0.04, respectively. Linear sweep voltammetry (LSV) displayed that the PCE potential window is 2.1 V. The desired mixture of activated carbon (AC) and carbon black was used to fabricate the electrodes of the EDLC. Cyclic voltammetry (CV) was carried out by sandwiching the PCEs between two carbon-based electrodes, and it revealed an almost rectangular shape. The EDLC exhibited specific capacitance, energy density, and equivalent series resistance with average of 160.07F/g, 18.01Wh/kg, and 51.05Ω, respectively, within 450 cycles. The EDLC demonstrated the initial power density as 4.065 × 10³ W/Kg. Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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Open AccessCommunication

Stretchable Electronics Based on Laser Structured, Vapor Phase Polymerized PEDOT/Tosylate

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Polymers 2020, 12(8), 1654; https://doi.org/10.3390/polym12081654 - 25 Jul 2020

Cited by 2 | Viewed by 2525

Abstract

The fabrication of stretchable conductive material through vapor phase polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) is presented alongside a method to easily pattern these materials with nanosecond laser structuring. The devices were constructed from sheets of vapor phase polymerized PEDOT doped with tosylate on pre-stretched [...] Read more.

The fabrication of stretchable conductive material through vapor phase polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) is presented alongside a method to easily pattern these materials with nanosecond laser structuring. The devices were constructed from sheets of vapor phase polymerized PEDOT doped with tosylate on pre-stretched elastomeric substrates followed by laser structuring to achieve the desired geometrical shape. Devices were characterized for electrical conductivity, morphology, and electrical integrity in response to externally applied strain. Fabricated PEDOT sheets displayed a conductivity of 53.1 ± 1.2 S cm⁻¹; clear buckling in the PEDOT microstructure was observed as a result of pre-stretching the underlying elastomeric substrate; and the final stretchable electronic devices were able to remain electrically conductive with up to 100% of externally applied strain. The described polymerization and fabrication steps achieve highly processable and patternable functional conductive polymer films, which are suitable for stretchable electronics due to their ability to withstand externally applied strains of up to 100%. Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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Open AccessEditor’s ChoiceArticle

Development of Poly(l-Lactic Acid)-Based Bending Actuators

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Verónica de Zea Bermudez

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Senentxu Lanceros-Méndez

Polymers 2020, 12(5), 1187; https://doi.org/10.3390/polym12051187 - 22 May 2020

Cited by 7 | Viewed by 2473

Abstract

This work reports on the development of bending actuators based on poly(l-lactic acid) (PLLA)/ionic liquid (IL) blends, through the incorporation of 40% wt. of the 1-ethyl-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) IL. The films, obtained by solvent casting at room temperature and 50 °C, [...] Read more.

This work reports on the development of bending actuators based on poly(l-lactic acid) (PLLA)/ionic liquid (IL) blends, through the incorporation of 40% wt. of the 1-ethyl-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) IL. The films, obtained by solvent casting at room temperature and 50 °C, were subjected to several post-thermal treatments at 70, 90, 120 and 140 °C, in order to modify the crystallinity of the films. The influence of the drying temperature and of [Emim][TFSI] blending on the morphological, structural, mechanical and electrical properties of the composite materials were studied. The IL induced the formation of a porous surface independently of the processing conditions. Moreover, the [Emim][TFSI] dopant and the post-thermal treatments at 70 °C promoted an increase of the degree of crystallinity of the samples. No significant changes were observed in the degree of crystallinity and Young Modulus for samples with thermal treatment between 70 and 140 °C. The viability of the developed high ionic conductive blends for applications as soft actuators was evaluated. A maximum displacement of 1.7 mm was achieved with the PLLA/[Emim][TFSI] composite prepared at 50 °C and thermally treated at 140 °C, for an applied voltage of 10 Vpp, at a frequency of 100 mHz. This work highlights interesting avenues for the use of PLLA in the field of actuators. Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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Open AccessArticle

Assessing the Influence of the Sourcing Voltage on Polyaniline Composites for Stress Sensing Applications

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Andrés Felipe Cruz-Pacheco

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Leonel Paredes-Madrid

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Jahir Orozco

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Jairo Alberto Gómez-Cuaspud

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Carlos R. Batista-Rodríguez

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Carlos Andrés Palacio Gómez

Polymers 2020, 12(5), 1164; https://doi.org/10.3390/polym12051164 - 19 May 2020

Cited by 8 | Viewed by 2238

Abstract

Polyaniline (PANI) has recently gained great attention due to its outstanding electrical properties and ease of processability; these characteristics make it ideal for the manufacturing of polymer blends. In this study, the processing and piezoresistive characterization of polymer composites resulting from the blend [...] Read more.

Polyaniline (PANI) has recently gained great attention due to its outstanding electrical properties and ease of processability; these characteristics make it ideal for the manufacturing of polymer blends. In this study, the processing and piezoresistive characterization of polymer composites resulting from the blend of PANI with ultra-high molecular weight polyethylene (UHMWPE) in different weight percentages (wt %) is reported. The PANI/UHMWPE composites were uniformly homogenized by mechanical mixing and the pellets were manufactured by compression molding. A total of four pellets were manufactured, with PANI percentages of 20, 25, 30 and 35 wt %. Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to confirm the effective distribution of PANI and UHMWPE particles in the pellets. A piezoresistive characterization was performed on the basis of compressive forces at different voltages; it was found that the error metrics of hysteresis and drift were influenced by the operating voltage. In general, larger voltages lowered the error metrics, but a reduction in sensor sensitivity came along with voltage increments. In an attempt to explain such a phenomenon, the authors developed a microscopic model for the piezoresistive response of PANI composites, aiming towards a broader usage of PANI composites in strain/stress sensing applications as an alternative to carbonaceous materials. Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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Open AccessArticle

Triple Layer Tungsten Trioxide, Graphene, and Polyaniline Composite Films for Combined Energy Storage and Electrochromic Applications

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Hailong Lyu

Polymers 2020, 12(1), 49; https://doi.org/10.3390/polym12010049 - 30 Dec 2019

Cited by 23 | Viewed by 3043

Abstract

Different polyaniline (PANI)-based hybrid films were successfully prepared by electro-polymerizing aniline monomers onto pre-spin-coated indium tin oxide (ITO) glass slides with WO₃, graphene, or WO₃/graphene films. Comparing with pristine PANI, the shifts of the characteristic peaks of PANI-based nanocomposites [...] Read more.

Different polyaniline (PANI)-based hybrid films were successfully prepared by electro-polymerizing aniline monomers onto pre-spin-coated indium tin oxide (ITO) glass slides with WO₃, graphene, or WO₃/graphene films. Comparing with pristine PANI, the shifts of the characteristic peaks of PANI-based nanocomposites in UV-visible absorption spectra (UV-vis) and Fourier transform infrared spectroscopy (FT-IR) indicate the chemical interaction between the PANI matrix and the nanofillers, which is also confirmed by the scanning electron microscope (SEM) images. Corresponding coloration efficiencies were obtained for the WO₃/PANI (40.42 cm² C⁻¹), graphene/PANI (78.64 cm² C⁻¹), and WO₃/graphene/PANI (67.47 cm² C⁻¹) films, higher than that of the pristine PANI film (29.4 cm² C⁻¹), suggesting positive effects of the introduced nanofillers on the electrochromic performance. The areal capacitances of the films were observed to increase following the order as bare WO₃ < WO₃/graphene < pristine PANI < WO₃/PANI < graphene/PANI < WO₃/graphene/PANI films from both the cyclic voltammogram (CV) and galvanostatic charge-discharge (GCD) results. The enhanced energy storage and electrochromic performances of the PANI-based nanocomposite films can be attributed to the capacitance contributions of the introduced nanofillers, increased PANI amount, and the rougher morphology due to the embedment of the nanofillers into the PANI matrix. This extraordinary energy storage and electrochromic performances of the WO₃/graphene/PANI film make it a promising candidate for combined electrochromic and energy storage applications. Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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Open AccessArticle

Allylamine PECVD Modification of PDMS as Simple Method to Obtain Conductive Flexible Polypyrrole Thin Films

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Robert Texidó

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Salvador Borrós

Polymers 2019, 11(12), 2108; https://doi.org/10.3390/polym11122108 - 15 Dec 2019

Cited by 4 | Viewed by 3035

Abstract

In this paper, we report a one-step method to obtain conductive polypyrrole thin films on flexible substrates. To do this, substrates were modified through allylamine plasma grafting to create a high amount of reactive amine groups on PDMS surface. These groups are used [...] Read more.

In this paper, we report a one-step method to obtain conductive polypyrrole thin films on flexible substrates. To do this, substrates were modified through allylamine plasma grafting to create a high amount of reactive amine groups on PDMS surface. These groups are used during polypyrrole particle synthesis as anchoring points to immobilize the polymeric chains on the substrate during polymerization. Surface morphology of polypyrrole thin films are modified, tailoring the polyelectrolyte used in the polypyrrole synthesis obtaining different shapes of nanoparticles that conform to the film. Depending on the polyelectrolyte molecular weight, the shape of polypyrrole particles go from globular (500 nm diameter) to a more constructed and elongated shape. The films obtained with this methodology reflected great stability under simple bending as well as good conductivity values (between 2.2 ± 0.7 S/m to 5.6 ± 0.2 S/cm). Full article

(This article belongs to the Special Issue Conducting Polymers for Advanced Applications)

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