Photoisomerization of electroactive polyimide/multiwalled carbon nanotube composites on the effect of electrochemical sensing for ascorbic acid

Abstract

We present the first investigation of photoisomerization of the azo-based electroactive polyimide (PI)/amino-functionalized multiwalled carbon nanotube (MWCNT) composite electrode on the effect of electrochemical sensing for ascorbic acid (AA). First, MWCNTs were grafted with 4-aminobenzoic acid in a medium of polyphosphoric acid/phosphorous pentoxide to obtain MWCNTs functionalized with 4-aminobenzoyl groups (AF-MWCNTs). Subsequently, photoactive and electroactive PI/AF-MWCNT composites (PEPACCs) were prepared by introducing pendant conjugated oligoaniline (amino-capped aniline trimer) in the main chain and azobenzene chromophores in the side chain, in the presence of AF-MWCNTs. Photoactive and electroactive PI (PEPI) and PEPACCs were characterized by 1 H NMR spectra, UV−visible absorption spectra, cyclic voltammetry (CV) and transmission electron microscopy. The CV study shows that the PEPACCs have higher electroactivity than PEPI. The redox and reversible photoisomerization (i.e. cis ↔ trans) behavior of PEPACCs was analyzed by in situ monitoring through systematic studies of CV and UV−visible spectroscopy. The light of the UV lamp was 365 nm. It should be noted that the sensor constructed from a trans-PEPACC-modified carbon-paste electrode (CPE) demonstrated a higher electrocatalytic activity by 2.75-fold and 1.12-fold towards the oxidation of AA compared with those constructed using a PEPI-and cis-PEPACC-modified CPE, respectively. The detection limit of the trans-PEPACC-modified electrode was 1.73-fold and 1.70-fold lower than that of PEPI-and cis-PEPACC-modified CPE. Moreover, the differential pulse voltammetry data showed that the trans-PEPACC-modified electrode had high electrochemical sensing ability for the determination of AA, dopamine and uric acid.

Modified Electrodes and Electrochemical Systems Switchable by Light Signals

“…Azobenzene monolayers bound to superconducting boron‐doped diamonds allowed photochemical control over their electronic properties and conductivity . The photoswitchable processes have been studied in nano‐size systems including single‐azobenzene molecules analyzed with STM , azobenzene‐functionalized Au nanoparticles , carbon nanotubes and graphene nanosheets . Photoisomerizable azobenzene monolayers were deposited on a source‐electrode of an organic field‐effect transistor resulting in optical modulation of charge injection and light‐controlled operation .…”

Carbon Nanotube-Conducting Polymer Composites as Electrode Material in Electroanalytical Applications

“…In recent years, many research groups have developed new types of electrochemical sensors and methods for AA detection. In one of the studies, CNT-CP composites were prepared with a polyimide (PI)/aminofunctionalized MWCNT composite material for the determination of AA [74].…”

Comparative Studies of CPEs Modified with Distinctive Metal Nanoparticle-Decorated Electroactive Polyimide for the Detection of UA

“…Moreover, OAEPs report good thermal stability [ 39 ], electrochemical activity [ 40 , 41 ], biomedical applications [ 42 ], electrochromic properties [ 43 ], and electrochemical [ 44 ] and conductivity studies [ 45 ]. Additionally, in our previous studies, OAEPs have been used for electrochemical sensing of ascorbic acid [ 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ].…”