Three-dimensional Polypyrrole Research Articles

In situ polymerization of three-dimensional polypyrrole aerogel for efficient solar-driven interfacial evaporation and desalination

Solar-driven interfacial evaporation (SIE) and desalination is a promising approach to mitigate the scarcity of freshwater resources. Here, a three-dimensional polypyrrole (3D PPy) aerogel was prepared by in situ polymerization of pyrrole to serve as an independent evaporator. The interconnected pore structure and super-hydrophilicity enabled PPy evaporators with rapid water transport to the top interface (< 5 s). The hydrogen interaction between polymer chains and water molecules induced large amount of intermediate water, thereby reducing the evaporation enthalpy of water in PPy aerogels. As a result, the optimized PPy aerogel attained an evaporation rate of 2.90 kg m−2 h−1 and an energy conversion efficiency of 114% under 1 sun irradiation. Moreover, the generated steam can be accelerated by the convection and an evaporation rate as high as 6.10 kg m−2 h−1 was realized at 2.5 m s−1. The rapid water transport also enabled PPy aerogel with high-efficiency of self-salt-discharge and efficient desalination for 3.5 wt% brine under 2.5 m s−1. In the outdoor SIE experiment, the excellent evaporation performance was achieved at 12:40 (7.04 kg m−2 h−1 under 74.2 mW cm−2 of solar intensity and 2.5 m s−1 of convective flow), and the cumulative evaporation of 41.50 kg m−2 for successive 9 h was obtained. After the evaporation of simulated seawater and heavy metal wastewater, the concentration of collected fresh water could be reduced about 2–3 orders of magnitude. This 3D PPy evaporation platform with high light absorption, porous structure, super-hydrophilic property, effective steam diffusion, and excellent salt resistance provides an effective way to develop advanced solar-driven water treatment technology.

Polypyrrole hydrogel with near-infrared light-driven nitric oxide release and photothermal activities for rapid synergistic sterilization and infected wound therapy

Developing low-cost and easy-accessible phototherapy agents with a high sterilization efficiency is urgently needed tackling the increasingly dangerous of bacterial infections. Herein, a broad-spectrum antimicrobial agent (i.e., PP-Mo-NO) with near-infrared laser (NIR) driven nitric oxide (NO) release capacity derived from the assemble of a heat-sensitive NO donor (N, N′-di-sec-butyl-N, N′-dinitroso-1, 4-phenylenediamine, BNN6) with freeze-dried three-dimensional polypyrrole hydrogel crosslinked by the sulfonated dimolybdenum-salen (PP-Mo), was synthesized for the rapid and effective eradicating of Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Upon 808 nm laser irradiation, PP-Mo-NO showed not only superb photothermal efficacy (79.88 %), but also precisely controllable NO release capacity, generating oxidative/nitrosative stress. Within 10 mins of irradiation (1.0 W cm−2), PP-Mo-NO with co-amplified photothermal (PTT)/NO synergetic antibacterial activity presented sterilization rates beyond 99.1% against both the E. coli and S. aureus at a relatively low concentration (100 µg mL−1). Meanwhile, in vivo experiments demonstrated the great application potential of PP-Mo-NO which could effectively kill bacteria at the site of infection, and repair the open infectious wounds, thereby accelerating the tissue reconstruction.

Synergistic effects of chloride anions and carboxylated cellulose nanocrystals on the assembly of thick three-dimensional high-performance polypyrrole-based electrodes

Porous three-dimensional (3D) structures generally improve the performance of electrodes by increasing their active surface area and the diffusion speed of electrolyte ions during charging/discharging. Three-dimensional polypyrrole (PPy) based films were created by electrodepositing PPy in the presence of varying amounts of chloride anions (Cl−) and polyanionic ribbonlike nanoparticles (carboxylated cellulose nanocrystals (CNC-COO−)) as scaffold material. The assembly mechanism of the 3D PPy electrodes combines the effect of different nucleation and growth mechanisms during electropolymerization and deposition of the formed PPy with CNC-COO− and with Cl−. The highest area capacitance of these electrode materials was 1.39 F cm−2 (150.2 F g−1) at a current density of 1 mA cm−2 (0.1 A g−1). More importantly, at a high current density of 20 mA cm−2 (2.2 A g−1), the thick (ca. 130 μm), 3D, and high mass loading (9.2 mg cm−2) Cl−:CNC-COO−/PPy films exhibited an excellent areal capacitance of 0.85 F cm−2 (70.8 F g−1), increasing about 16% over CNC-COO−/PPy films prepared without Cl− present during electrodeposition. In addition, an aqueous Cl−:CNC-COO−/PPy (with Cl−:CNC-COO− = 2.0) symmetric supercapacitor had an outstanding energy density of 41.15 μWh cm−2 (4.46 Wh kg−1) and excellent cycling stability, while even improving on its original areal capacitance (to 111.2% of its original capacitance) after cycling 3000 cycles at 8 mA cm−2, indicating their potential in energy storage devices.

Three-dimensional polypyrrole induced high-performance flexible piezoelectric nanogenerators for mechanical energy harvesting

Flexible piezoelectric nanogenerators (FPNGs) have received tremendous attention in terms of harvesting mechanical energy and driving portable devices. However, the weak interactions and interfacial defects between the fillers and matrix hinder from improving the flexibility and electromechanical properties of the composites, which limits the practical applications of nanogenerators. In this work, high-performance FPNGs based on all-organic composite thin films comprising of three-dimensional polypyrrole (3D PPy) and poly(vinylidene fluoride -hexafluoropropylene) [P(VDF-HFP)] are fabricated for the first time. The composite films exhibit excellent ferroelectric and piezoelectric properties, mainly resulting from the strong interfacial bonding between 3D PPy and the P(VDF-HFP) matrix. As a result, the FPNG prepared from the composites loaded with 5 wt% 3D PPy achieve considerable piezoelectric outputs (average power density of 5.52 μW/cm2 and peak power density of 10.84 μW/cm2). Meanwhile, the FPNGs can effectively obtain mechanical energy from human activities and still show a stable output after continuous operation over 3000 cycles. This work provides a novel idea to design and fabricate high-performance FPNGs through introducing conductive polymers into the matrix.

Facile synthesis of palladium-decorated three-dimensional conducting polymer nanofilm for highly sensitive H2 gas sensor

Hydrogen gas is a topic of considerable interest because of its critical importance to various applications in the fuel cell, aerospace and automotive industries. However, because it is highly flammable at low concentrations and causes asphyxiation at higher concentrations, it is crucial to implement an appropriate system to monitor hydrogen gas. In this report, we illustrate the facile synthesis of palladium-decorated three-dimensional conducting polymer nanofilms (PPyPds) for the detection of hydrogen gas. PPyPds are formed directly on the electrode through a modified electrodeposition process. The resulting PPyPd-based sensor is highly sensitive (down to 5 ppm) and binds hydrogen reversibly at ambient conditions, owing to the uniform distribution of palladium on the three-dimensional polypyrrole surface.

Three-Dimensional Polypyrrole Nano-Network with Sb Nanocrystals as Electrode Material for Sodium-Ion and Lithium-Ion Batteries

In this work, we develop an approach to synthesize a nanoscale structure with Sb nanocrystals and polypyrrole nano-network (Sb@ppy NNW) from the reduction of SbCl3 and the polymerization and crosslinking of pyrrole. The Sb@ppy NNW exhibits excellent electrochemical characteristics with incessant conduction paths for fast transfer of electrons, short paths for fast diffusion/migration of ions and large contact area between active material and electrolyte for the storage of Na/Li. The Sb@ppy NNW is used as active material in the working electrode for lithium-ion half cells and sodium-ion half cells. The sodium-ion half cells possess excellent cycling stability with a high specific capacity of 510 mA h g−1 at a current density of 100 mA g−1 and 463 mA h g−1 after 100 cycles at a current density of 500 mA g−1, and superior rate performance with a specific capacity of 635.6 mA h g−1 even at a current density of 1600 mA g−1. The specific capacities for the lithium-ion half cells are 660 mA h g−1 after 100 cycles at a current density of 100 mA g−1 and 635.6 mA h g−1 even at a current density of 1600 mA g−1.

Tailoring Three-Dimensional Composite Architecture for Advanced Zinc-Ion Batteries.

Rechargeable aqueous Zn-ion batteries (ZIBs) are of considerable interest for future energy storage. Their main limitation, however, is developing suitable cathode materials capable of sustaining the Zn2+ repeated intercalation/deintercalation. Herein, a three-dimensional polypyrrole (PPy)-encapsulated Mn2O3 composite architecture is developed for advanced ZIBs. The engineering can be easily realized via in situ phase transformation of MnCO3 microboxes with subsequent self-initiated polymerization of PPy. The abundant open-up pores (∼30 nm) throughout the construction accelerate ion migration and provide a more active interface for Zn2+ storage in the Mn2O3@PPy bulk electrode. Meanwhile, the PPy skin uniformly wrapped on the Mn2O3 microbox not only guarantees a good conductive network for faster electron transport but also inhibits the dissolution of Mn2O3 and protects the integrity of the electrode from structural damage. As a result, the Mn2O3@PPy electrode can operate at reversible capacity exceeding those of most other cathode materials, but can still provide longer lifetime (no capacity decay over 2000 cycles at 0.4 A g-1) and higher rate performance than others. Furthermore, theoretical studies show the H+ and Zn2+ coinsertion storage mechanism and reaction dynamics. The results show that this three-dimensional Mn2O3@PPy architecture is a promising cathode material for high-performance ZIBs.

Stretchable 3D polymer for simultaneously mechanical energy harvesting and biomimetic force sensing

Stretchability is an essential element for wearable electronics. Creating intelligent devices using stretchable polymers, which can simultaneously harvest mechanical energies and mimic the properties of fast adapting (FA) receptors, could be of significant importance for plastic bioelectronics and transistors. In this paper, we report an all-organic triboelectric nanogenerator (TENG) that enables both energy harvesting and biomimetic pressure sensing on the base of three-dimensional polypyrrole (PPy) network. By combining with polydimethylsiloxane (PDMS) and BaTiO3 nanoparticles, this composite triboelectric interface shows not only an enhanced uniaxial stretchability of up to 310%, but also a high short circuit current density of 18.0 mA m−2 in response to the environment or human motions. Such an excellent electric response further enables the sensitive detection of ambient mechanical energy. For example, the sensitivities of this stretchable device to acceleration, static and dynamic pressures are of 1.03 µA s2·m−1, 12.61 pF·kPa−1 and 57.78 µA MPa−1, respectively. In addition, sensitive responses to bending and curling force are also demonstrated. These results demonstrate an ideal way for developing self-driven electronic skins and biomimetic tactile sensors with intriguing flexibility, stretchability and sustainability.

A facile template approach for the synthesis of mesoporous Fe3C/Fe-N-doped carbon catalysts for efficient and durable oxygen reduction reaction

Facile synthetic approaches toward the development of efficient and durable nonprecious metal catalysts for the oxygen reduction reaction (ORR) are very important for commercializing advanced electrochemical devices such as fuel cells and metal-air batteries. Here we report a novel template approach to synthesize mesoporous Fe-N-doped carbon catalysts encapsulated with Fe3C nanoparticles. In this approach, the layer-structured FeOCl was first used as a template for the synthesis of a three-dimensional polypyrrole (PPy) structure. During the removal of the FeOCl template, the Fe3+ can be absorbed by PPy and then converted into Fe3C nanoparticles and Fe-N-C sites during the pyrolyzing process. As a result, the as-prepared catalysts could exhibit superior electrocatalytic ORR performance to the commercial Pt/C catalyst in alkaline solutions. Furthermore, the Zn-air battery assembled using the mesoporous carbon catalyst as the air electrode could surpass the commercial Pt/C catalyst in terms of the power density and energy density.

Self-assembled ultralight three-dimensional polypyrrole aerogel for effective electromagnetic absorption

A facile self-assembled polymerization method has been used to form pyrrole to an ultralight three-dimensional (3D) polypyrrole (PPy) aerogel. It exhibits an effective electromagnetic absorption (EA) bandwidth (deeper than −10 dB), which was characterized as 6.2 GHz when the filler loading is only 7 wt. % in paraffin based composite. This 3D-PPy aerogel can be considered as a light weight, low adjunction, thin thickness, and high performance EA material.

Enhanced photovoltaic performances of quasi-solid-state dye-sensitized solar cells using a novel conducting gel electrolyte

The extension of electrocatalytic reaction area toward iodides is expected to significantly accelerate the recovery of redox couples and therefore photovoltaic performances of quasi-solid-state dye-sensitized solar cells (DSSCs). To improve the cell properties of DSSC, a three-dimensional polypyrrole imbibed poly(hydroxyethyl acrylate)/poly(ethylene glycol) gel electrolyte has been successfully synthesized using the adsorption behavior of amphiphilic poly(hydroxyethyl acrylate)/poly(ethylene glycol) to pyrrole monomers. Resultant gel electrolyte is thoroughly characterized by spectral analysis and electrochemical characterizations. In comparison with pure poly(hydroxyethyl acrylate)/poly(ethylene glycol) gel electrolyte, the incorporation of electron-conducting polypyrrole shows enhanced physicochemical properties. Interconnected micropores within the gel electrolyte provides space for holding I−/I3− liquid electrolyte, giving an ionic conductivity of 21.08 mS cm−1. The integration of polypyrrole on poly(hydroxyethyl acrylate)/poly(ethylene glycol) gives a higher electrocatalytic activity because of the extension of electrocatalytic reaction toward I−/I3− couple from counter electrode/gel electrolyte interface to the three-dimensional framework of gel electrolyte. The resultant DSSC from polypyrrole imbibed poly(hydroxyethyl acrylate)/poly(ethylene glycol) gel electrolyte displays a light-to-electric conversion efficiency of 7.02% in comparison with 5.76% from pure poly(hydroxyethyl acrylate)/poly(ethylene glycol). The new concept along with easy fabrication promise the conducting polymer imbibed amphiphilic gel electrolytes good candidates in robust DSSCs.

Polypyrrole Micro/Nanostructure Prepared Using Azo Dyes with Different Substituents

This contribution deals with simple way of polypyrrole structure modification. Using azo dyes in polymerization reaction as soft-template with similar molecular structure but different type and distribution of substitution groups lead to formation of one-dimensional and newly also three-dimensional polypyrrole micro/nanostructures. These structures are characteristic with geometrical symmetry and uniformity. Geometry of prepared structures was studied by scanning electron microscopy (SEM) and by methods of image analysis; nanotubes are hundreds of nm in diameter and units of μm in length, new tree-dimensional structures have units of μm in diameter. Infrared spectra (ATR-FTIR) confirmed that azo dyes work only as intermediate supporting structures without reaction with polypyrrole.

Pyrene-Loaded Polypyrrole Microvessels

The encapsulation of guest molecules within polymeric hollow nano- or microscale structures is a rapidly developing field of interdisciplinary research due to a variety of applications ranging from drug delivery and sensor fabrication to nanoscale synthesis and bioinspired mineralization. We report on the encapsulation of pyrene within three-dimensional polypyrrole microvessels synthesized by precipitation polymerization of pyrrole onto toluene droplets that contain pyrene. Steady state and time-resolved fluorescence measurements show that the optical response and dynamics of encapsulated pyrene is significantly different from that in the free solution, likely due to interactions with oligomeric species generated during the polymerization process that partition into the organic core of the microvessel. Our results indicate that the encapsulation process can have a significant influence on the local environment of encapsulated species, an issue that is critical from the perspective of potential synthetic or medical applications.

Symmetric redox supercapacitor based on micro-fabrication with three-dimensional polypyrrole electrodes

To achieve higher energy density and power density, we have designed and fabricated a symmetric redox supercapacitor based on microelectromechanical system (MEMS) technologies. The supercapacitor consists of a three-dimensional (3D) microstructure on silicon substrate micromachined by high-aspect-ratio deep reactive ion etching (DRIE) method, two sputtered Ti current collectors and two electrochemical polymerized polypyrrole (PPy) films as electrodes. Electrochemical tests, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatical charge/discharge methods have been carried out on the single PPy electrodes and the symmetric supercapacitor in different electrolytes. The specific capacitance (capacitance per unit footprint area) and specific power (power per unit footprint area) of the PPy electrodes and symmetric supercapacitor can be calculated from the electrochemical test data. It is found that NaCl solution is a good electrolyte for the polymerized PPy electrodes. In NaCl electrolyte, single PPy electrodes exhibit 0.128 F cm −2 specific capacitance and 1.28 mW cm −2 specific power at 20 mV s −1 scan rate. The symmetric supercapacitor presents 0.056 F cm −2 specific capacitance and 0.56 mW cm −2 specific power at 20 mV s −1 scan rate.

Preparation of Surface-Supported Polypyrrole Capsules Using a Solidified Droplets Template Approach

Three-dimensional polypyrrole microcapsules were prepared via chemical deposition of the polymer onto tetradecanol particles supported on solid substrates. The growing polymer deposited onto the particle surface yielded hemispherical containers that encapsulated the tetradecanol contents. Mixing the tetradecanol with other chemical species, like fluorescent dyes, allowed the entrapment of these species within the containers. It was shown that by controlling the temperature, one could reversibly melt and solidify the tetradecanol content of the capsules. The tuning of the fluorescence intensity emitted from the capsules could thus be controlled. The polypyrrole structures were characterized using several complementary experimental methods. These included microscopic (scanning electron microscopy, atomic force microscopy, and optical microscopy) and spectroscopic techniques (steady-state fluorescence, ultraviolet-visual light absorption, and infrared spectroscopy) as well as conductivity and contact angle measurements.