Microporous Polyaniline Research Articles

Sulfuric acid-doped conjugated microporous poly(aniline)s enabled unconventional Hg (II) adsorption from aqueous solution

New strategies are required to modify adsorbents that possess numerous accessible chelating sites with high utilization, in order to achieve both rapid uptake and high capacity for the contaminants, which are still urgently needed. This study introduces a novel integration of a conjugated microporous polymer (CMP) material with conventional polyaniline, representing the first instance of such a combination. By amalgamating the doping properties of polyaniline with the highly stable structure and extensive microporous attributes of CMP, we achieve a synergistic effect. The conjugated microporous polyaniline is subjected to a concentrated sulfuric acid modification (SD-CMPA), enabling simultaneous oxidation, doping, and pore channel modification in a single step. The resulting SD-CMPA exhibits a record-breaking maximum adsorption capacity for Hg2+, reaching as high as 1720 mg·g−1, as well as a benchmark distribution coefficient of 2.5 × 108 mL·g−1. Moreover, it demonstrates robust reusability, retaining over 96% of its adsorption capacity for at least six cycles. These remarkable features enable the achievement of ultra-deep-water purification to 0.452 ppb in an effective manner. The impressive performance of SD-CMPA can be attributed to the abundance of nitrogen-containing groups, particularly the tertiary amine nitrogen in the material skeleton, as supported by X-ray photoelectron spectroscopy and density functional theory calculations. The results presented in this study demonstrate the exceptional potential of SD-CMPA for high-performance environmental remediation.

Isolating metallophthalocyanine sites into graphene-supported microporous polyaniline enables highly efficient sensing of ammonia

The successful isolation of metal phthalocyanines into graphene-supported microporous polyanilines results in rich exposure to active sites, rapid electron transfer and efficient gas transport channels, which synergically enhance NH3 sensing.

Self-Reducible Conjugated Microporous Polyaniline for Long-Term Selective Cr(VI) Detoxication Driven by Tunable Pore Dimension.

A simple methodology to controllably tune the pore size and Cr(VI) adsorption capacity was reported herein to synthesize a new series of conjugated microporous polyaniline (CMPA) networks. The well-ordered micropore was acquired through our very recent Bristol-Xi'an Jiaotong method, and the pore size was fine-tuned to increase with the increasing length of linkers, mimicking covalent organic frameworks and metal organic frameworks very much. A selective ultrahigh adsorption capacity of 520.8 mg/g was achieved by CMPA-1 in a very fast manner, with a systematically gradual decrease to 173.9 mg/g of CMPA-3 by enlarging the pore size of the networks, featuring tunable adsorption capacity through molecular-size-recognition mechanism. Additionally, our robust CMPA networks, which were constructed by Buchwald-Hartwig chemistry, showed the complete function of polyaniline and were capable of providing, besides large storage capacity for Cr(III), at least 10 reductant/desorption-free cycles for effective Cr(VI) reduction and detoxication through their novel self-reducible redox states. Outcomes showed that our CMPAs could be applied as new self-healing scavengers in the next generation for Cr(VI) storage and detoxication.

Electrochemical synthesis of microporous polyaniline films using foam templates prepared by ultrasonication.

We report a new soft template method for the synthesis of unique polyaniline (PANI) films with microporous structures. In this process, ultrasonication is used to foam an electrolyte solution containing a surfactant, which is subsequently employed as a soft template for PANI growth via the electrochemical polymerization of aniline. Analysis by scanning electron microscopy demonstrates that the resulting PANI films contain numerous micropores. These microporous PANI films exhibit faster charging (doping) and discharging (dedoping) current responses compared to ordinary flat films of the same material.

Molten salt assisted synthesis of microporous polyaniline nanosheets with superior gas sorption properties

Porous polyaniline (PANI) nanosheet has unique structure and properties that can be applied in gas separation, gas storage, and energy storage and conversion devices. To date, it is still a great challenge to construct microporous PANI nanosheet materials. Here, we present an inorganic salt template pyrolysis route for the direct synthesis of ultrathin PANI nanosheets with well-defined microporous structure from hexaaminobenzene monomer. The obtained PANI nanosheets give an ultrathin thickness of 1.6 nm, high surface area (∼395 m2 g−1), and well-defined microporous structure (centered at ∼0.54 nm). The PANI nanosheets with plenty of micropores exhibit superior gas sorption property for CO2 and CH4 at room temperature, which is also expected to improve the performances of PANI nanosheets in other application fields.

Synthesis and characterization of electropolymerized molecularly imprinted microporous polyaniline films for solar cell applications

AbstractThe solicitude to molecularly imprinted conjugated polymers is flourishing due to their auspicious properties for a myriad of technological and industrial applications. The preparation conditions strongly affect the structure, optical, thermal, and electrical properties of these polymers. Subsequently, a consistent contemplation is desired to entrench consanguinity between processing stipulations and these variables. Here, molecularly imprinted polyaniline films, based ascorbic acid as a template, have been synthesized via electropolymerization technique. This template has been extracted from the films to create microporous polyaniline films. The morphology and structure of these films were investigated using X‐ray diffraction and Fourier transform infrared spectroscopy. Thermogravimetric test showed an enhancement in the thermal stability of molecular imprinted polyaniline compared with non‐imprinted techniques. The optical measurements showed that the rate of light absorption is increased twice with low transmission and reflection. The electrical conductivity increased by four orders with activation energy of 0.30 eV. The optoelectronic measurements of molecularly imprinted microporous polyaniline films showed that the filling factor and external quantum efficiency are enhanced compared with non‐imprinted polyaniline films. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

Degradation of microporous polyaniline film by UV–ozone treatment

Thin microporous polyaniline films in the emeraldine-base form (PANI-EB) have been prepared electrochemically at a potential of 0.8 V. The effect of ozone treatment on the structural changes of polyaniline thin films has been investigated using X-ray photoelectron spectroscopy, SEM and EPR. Surface analysis showed that oxidation occurs mainly at the carbon atoms, resulting in the formation of C O and COOH species. The degradation reaction seems to be preferentially directed towards the quinoneimine units. At high extent of carbon oxidation, UV–ozone treatment may involve the direct oxidation of the nitrogen atoms to form –NO x species.

Application of microporous polyaniline counter electrode for dye-sensitized solar cells

An inexpensive microporous polyaniline (PANI) is used as a substitute for platinum to construct the counter electrode in dye-sensitized solar cells (DSSCs). The PANI counter electrode with microporosity and a size diameter of about 100 nm possesses lower charge-transfer resistance and higher electrocatalytic activity for the I 3 - / I - redox reaction than Pt electrode does. The overall energy conversion efficiency of the DSSC with PANI counter electrode reaches 7.15%, which is higher than that of the DSSC with Pt counter electrode. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow PANI electrode to be a credible alternative for DSSCs.

EPR and electrical conductivity in microporous polyaniline

We have studied a series of microporous polyaniline (PANI) samples, each of the structure with micro-channels and micro-caves inside (a diameter of 1.5–2.5 μm), formed as a non-periodic network of microrods. Microporous polyaniline is a paramagnetic material and strong EPR signals with the g-factor in the range of 2.0030–2.0032 and the line width Δ B between 1.80 and 6.50 Gs have been measured for samples of various electrical conductivity. The EPR line asymmetry is high (almost 1.5) in the case of PANI samples of the highest electrical conductivity (0.35 S/cm). We found that lithium cations present in the reaction medium can stabilise values of the EPR line asymmetry parameter and g-factor observed for PANI samples prepared in such conditions. Lithium cations are able to influence the intermolecular hydrogen bonding which is essential for the interchain coupling leading to an increase in the EPR line asymmetry and a higher electrical conductivity. Thus, the properties of PANI samples are modified by lithium cations.