The Use of Conductive Polymers Embedded Macro Porous Pei and Ionic Liquid Form of Pei Cryogels for Potential Conductometric Sensor Application to CO2

Sahin Demirci,Nurettin Sahiner

doi:10.3390/jcs4010027

Abstract

Polyethyleneimine (PEI) cryogels with interconnected superporous morphology were synthesized via the cryopolymerization technique. Then, conductive polymers, poly(Aniline) (PANi), poly(Pyrrole) (PPy), and poly(Thiophene) (PTh) were prepared within these PEI cryogels. Then, the conductive polymer embedding PEI composites’ characterization was carried morphologically using scanning electron microscope (SEM) by means of Fourier Transform Infrared Radiation (FT-IR) spectrometer, and by means of electrical conductivity measurements using an electrometer. Among all the prepared cryogel conductive polymer composites, the highest value in terms of conductivity was determined for PEI/PANi cryogel composites with 4.80 × 10−3 S.cm−1. Afterward, to prepare polymeric ionic liquid (PIL) forms of PEI and PEI/PANi composites. To assess the effect of anions on the conductivities of the prepared composites, PEI-based cryogels were anion ex-changed after protonation with HCl by treatment of aqueous solutions of sodium dicyanamide (Na+[N(CN)2]−), ammonium hexafluorophosphate (NH4+[PF6]−), sodium tetrafluoroborate (Na+[BF4]−), and potassium thiocyanate (K+[SCN]−), separately. Furthermore, PEI-based cryogel composites and their PIL forms were tested as a sensor for CO2 gas. The higher conductivity changes were observed on bare PEI cryogel and PEI+[BF4]− PIL cryogels with 1000-fold decrease on conductivity upon 240 min CO2 exposure. The sensitivity and recovery percent of bare PEI and PEI+[BF4]− PIL cryogels were shown almost the same with a two-fold decrease in the presence of 0.009 mole of CO2 gas, and approximately 30% recovery after the fifth consecutive reuse.

Highlights

Carbon dioxide (CO2) exist in the mixture of atmospheric gas and fossil fuels as a result of industrial discharge and forest fires and natural disasters
PEI cryogels that were prepared by using Mn: 1800 g/mole was used as a template for in situ conductive polymers, e.g., PANi, PPy, and PTh synthesis
The Py and Th loaded PEI cryogels were placed into 0.5 M 250 mL FeCl3 solution in DI water at room temperature for 2 h, and in 0.3 M 100 mL FeCl3 solution in chloroform at 65 ◦C for 16 h to initiate the corresponding in situ polymerization of Py and Th within PEI cryogels, respectively

Summary

Introduction

Carbon dioxide (CO2) exist in the mixture of atmospheric gas and fossil fuels (coal, natural gas, petroleum, and derivatives) as a result of industrial discharge and forest fires and natural disasters. The contribution of CO2 is 80%–85% in the atmosphere, derived from fossil fuels, and about 15%–20% from the respiration of living things and the decomposition of organic matter from microscopic organisms [2]. In addition to the rapid increase of fossil fuel use, the destruction of forests and vegetation plankton, which consume tons of CO2 during photosynthesis, have reached the highest level of CO2 in the atmosphere over the past 160,000 years and analyses project that this increase will continue [3]. The emission of produced CO2 gas into the world atmosphere is an international issue due to the influence of greenhouse gases with this uncontrolled emission that the Kyoto protocol tried to limit. The selective separation of CO2 from gas mixtures, detection of CO2, and harmless storage "CO2 sequestration" is considered of paramount significance [4]

Methods

Results

Conclusion