Metal-phthalocyanine modified doped polyaniline for VOC sensing applications

Abstract

The identification and measurement of volatile organic compounds (VOCs) is needed in a variety of applications including air quality monitoring, air pollution measurement, food quality monitoring, and breath analysis-based disease diagnosis etc. The monitoring of the VOCs related to different applications areas can ensure quality health and safety. Arrays of chemical sensors have the features to provide the required identification and measurement of the VOCs. Chemical sensors made from nanostructures of polyaniline (PANI) as the base sensing material have several advantages including tunable properties, room temperature sensing and the potential of being amenable to the printing processes. Metal (M) phthalocyanines (Pc), on account of different cavity structures, have the ability to selectively interact with different gases. In the reported studies most of the MPcs have been noncovalently deposited on the sensing platforms, or attached with the base polymer via π-π conjugation. The covalent bonding of MPcs with the sensing polymer may have several possible advantages including stability (no leaching or evaporation of the compounds), well-defined available interfaces for interaction and a longer operational lifetime. In this work, the camphor sulphonic acid (CSA) doped PANI nanostructures were covalently bonded with six metal embedded phthalocyanines (Cu-Pc, Mn-Pc, Zn-Pc, Fe-Pc, Ni-Pc and Co-Pc) and investigated as the sensor materials for the sensing of four VOCs: acetone, isopropanol, ethanol and formaldehyde, in a 150-500 ppb concentration range. The resultant chemical sensor array response in terms of relative change in resistance of the sensing materials upon VOC exposure was analysed using principal component analysis, which resulted in clear discrimination among the subjected VOCs, thus making it useful for selective VOC sensing applications.

The structural factors affecting the sensory properties of polyaniline derivatives

“…In this series of polymers, polyaniline is one of the promising materials for chemical sensors since its conductivity is highly sensitive to many chemical vapours through several different mechanisms including doping/dedoping, reduction/oxidation, swelling, and altering the polymer conformation. 19–25 Many toxic acids formed in the atmosphere can be detected using sensors based on PANI since they can protonate a polymer to form the emeraldine salt and increase the electrical conductivity of the polymer film. 18 The reverse process can also be used to detect certain gases, such as ammonia or organic amines, due to the deprotonation process and, as a result, a decrease in conductivity.…”

Phthalocyanines and Porphyrins/Polyaniline Composites (PANI/CuPctBu and PANI/TPPH2) as Sensing Materials for Ammonia Detection

“…While examples of the combination of PANI with metal oxides, NPs, carbon nanotubes, graphene, etc. are found in the literature, its combination with organic semiconductors such as phthalocyanines and porphyrins is less exploited [ 5 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Examples of these PANI-macrocycle combinations dedicated to gas sensors are also rare [ 5 , 19 , 23 ].…”

“…are found in the literature, its combination with organic semiconductors such as phthalocyanines and porphyrins is less exploited [ 5 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Examples of these PANI-macrocycle combinations dedicated to gas sensors are also rare [ 5 , 19 , 23 ]. Knowing that these MCs are potentially well documented [ 24 ] for their capacity to enhance sensitivity, we have focused on such a combination with PANI.…”

Multifunctional organic shockproof flexible sensors based on a composite of nickel phthalocyanine colourant, carbon nanotubes and rubber created with rubbing‐in technology

“…55 ms. 28 A resistive-type chemical sensor based on a composite of camphor sulphonic acid, nanostructured polyaniline and six MPcscopper phthalocyanine, manganese phthalocyanine, zinc phthalocyanine, iron phthalocyanine, nickel phthalocyanine and cobalt phthalocyanine-was fabricated over the range of 150-500 ppb for chemical investigations. 29 Then, in the same year, another group of scientists studied organic semiconductor-based, resistance-type gas sensors based on porous solid material (i.e. metal-organic frameworks).…”