Conductive polymer containing graphene aerogel composites as sensor for CO₂

Abstract

Graphene oxides (GO) prepared from graphite was used in the preparation of three‐dimensional (3D) super porous graphene aerogel (GA) by chemical reduction of GOs with l‐Ascorbic acid (l‐AA) via freeze drying. Then, the conductive polymers such as poly(aniline) (PANi), and poly(pyrrole) (PPy) within the superpores of 3D GA were prepared as GA/PANi and GA/PPy interpenetrating composites (IPC). The electrical conductivity of GA was measured as 4.17 × 10−2 ± 6.40 × 10−3 S/cm, whereas the electrical conductivity of GA/PANi was decreased to a half value and increased 3‐fold for GA/PPy IPC. Moreover, bare GA, GA/PANi, and GA/PPy IPCs were exposed to CO2 gas at room temperature, 20°C ± 2°C for potential sensor application by comparing the change in their electrical conductivities. Interestingly, it was found that the electrical conductivity of GA/PANi IPC composites was decreased 4,000 times upon 60 min CO2 gas exposure at ambient temperature and pressure suggesting potential CO2 gas sensor application of the prepared materials. POLYM. COMPOS., 40:E1208–E1218, 2019. © 2018 Society of Plastics Engineers

Graphene Aerogels for In Situ Synthesis of Conductive Poly(para-phenylenediamine) Polymers, and Their Sensor Application

“…The stretching vibrations at 1042 cm −1 and 873 cm −1 , respectively, were attributed to C-O stretching modes of vibrations in the alkoxy and the ether groups of GO [ 77 , 78 ]. The FT-IR peaks that appeared at 3516, 3411, and 1645 cm −1 are assigned to O-H groups, and the peak observed at 1758 cm −1 can further stem from the C=O groups, which is noticeable from the FT-IR spectrum of L-AA [ 34 ]. For GA, the spectral peaks are seen at 3511 and 3408 cm −1 and are attributed to the O-H stretching, and the peaks at 1749 cm −1 belong to C=O stretching vibrations.…”

“…The peaks that appeared at 1616 cm −1 can arise from the skeletal vibration of graphene sheets. From the oxidized graphene, GO sheets to their chemically reduced GA forms, the red shift can be readily noticed for C=O bands with the respective change from 1722 to 1749 cm −1 [ 34 ]. Additionally, the characteristic peaks of p(p-PDA), respectively, as stretching deformations of quinone at 1574 cm −1 , stretching deformations of benzene at 1491 cm −1 , and C-N stretching modes of a secondary aromatic amine at 1297 cm −1 , aromatic C-H in-plane bending modes at 1053 cm −1 , and the peaks at 828 cm −1 for out-of-plane deformations of C-H in the 1,4-disubstituted benzene ring can be realized from the given FT-IR spectra [ 76 ].…”

“…Graphene aerogels (GAs) were prepared by chemical reduction of prepared GOs following the cited literature with some modifications [ 34 , 67 ]. Concisely, 3.0 g of prepared GOs were dispersed in 500 mL DDW, following the modified Hummers method [ 39 , 68 ], with a final gravimetric concentration of 6 mg/mL.…”

“…GOs possess a good aqueous dispersibility and are electrical insulators because of the spoilage of the sp 2 hybridization. Preparation of reduced GOs (r-GOs) can be achieved to solve poor conductivity of GOs by treating them with different reducing agents such as hydroquinone, diazene (N 2 H 2 ), hydrazine(N 2 H 4 ), sodium borohydride(NaBH 4 ), sodium hydroxide (NaOH), sodium sulfide (Na 2 S), sodium bisulfate (NaHSO 3 ), ascorbic acid (C 6 H 8 O 6 ), and hydroiodic acid (HI) [ 34 , 35 ]. GOs have been reported in preparation for a variety of composite materials [ 36 ] such as metal composites [ 37 ], various polymers, hydrogels [ 38 ], and cryogels [ 39 ].…”

“…Composites of GAs can be prepared by which the desired properties of guest molecules along with GAs can be combined in a single physical entity. Various nanoarchitectures and polymers were generated in situ within GAs such as CoFe 2 O 4 nanoclusters [ 46 ], TiO 2 [ 47 ], and Co [ 48 ] nanocrystals, gold nanoparticles [ 49 ], Fe 3 O 4 nanoparticles [ 50 ], and quantum dots [ 51 ], along with some polymers such as polydimethylsiloxane [ 52 ], poly(aniline), poly(pyrrole) [ 34 , 53 ], and so on.…”