Protonation-Induced Enhanced Optical-Light Photochromic Properties of an Inorganic-Organic Phosphomolybdic Acid/Polyaniline Hybrid Thin Film

Abstract

A phosphomolybdic acid/polyaniline (PMoA/PANI) optical-light photochromic inorganic/organic hybrid thin film was successfully synthesized by protonation between the the multiprotonic acid phosphomolybdic acid (H3PO4·12MoO3) and the conductive polymer polyaniline. The stable Keggin-type structure of PMoA was maintained throughout the process. Protonation and proton transfer successfully transformed the quinone structure of eigenstate PANI into the benzene structure of single-polarized PANI in the PMoA/PANI hybridized thin film, and proton transfer transformed the benzene structure of single-polarized PANI back to the quinone structure of eigenstate PANI in the PMoA/PANI hybrid thin film, as verified by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The average distribution of PMoA/PANI was observed by atom force microscopy (AFM). Interestingly, protonation of PMoA caused PANI to trigger transformation of the quinone structure into the single-polarized benzene structure, which enhanced the electron delocalization ability and vastly enhanced the maximum light absorption of the PMoA/PANI hybrid thin film as confirmed by density functional theory (DFT), electrochemistry, and ultraviolet-visible spectroscopy (UV-Vis) studies. Under optical-light illumination, the pale-yellow PMoA/PANI hybrid thin film gradually turned deep blue, thus demonstrating a photochromic response, and reversible photochromism was also observed in the presence of hydrogen peroxide (H2O2) or oxygen (O2). After 40 min of optical-light illumination, 36% of the Mo5+ species in PMoA was photoreduced via a protonation-induced proton transfer mechanism, and this proton transfer resulted in a structural change of PANI, as observed by XPS, generating a dominant structure with high maximum light absorption of 3.46, when compared with the literature reports.

Microwave versus conventional promoted synthesis of fuel additives using graphitic carbon nitride supported catalysts

“…4b for the GCN–PMA material, was consistent with the presence of the metal in +6 oxidation state: the intense peak at 233.8 eV and the lower signal at 237.1 eV corresponded to Mo 3d 5/2 Mo 3d 3/2 , respectively. 33 Similarly, the deconvoluted spectrum of W 4f reported in Fig. 4c for the GCN–PTA material, showed two peaks assigned to the +6 oxidation state of W: the most intense one at 35.1 eV was attributed to W 4f 7/2 , while the second signal at 37.3 eV corresponded to W 4f 5/2 .…”

An Ultrahigh Linear Sensitive Temperature Sensor Based on PANI:Graphene and PDMS Hybrid with Negative Temperature Compensation

“…In the preparation of composite materials, it is necessary to fully consider the excellent properties of each ratio of materials to give full play to the advantages of composite . As a conventional flexible material, PDMS has good tensile and thermal expansibility, which makes it deform greatly in a slight temperature change interval.…”

“…9−11 In the preparation of composite materials, it is necessary to fully consider the excellent properties of each ratio of materials to give full play to the advantages of composite. 12 As a conventional flexible material, PDMS has good tensile and thermal expansibility, which makes it deform greatly in a slight temperature change interval. Graphene has the potential to improve the response speed and sensitivity of temperature sensors due to high thermal conductivity and high electron mobility.…”

Obtaining Reversible, Durable, High-Contrast Photochromism and Antibacterial Properties in a Flexible, Wearable Fiber Using Nanometer-Sized Polyoxotungstate

“…The first is introducing POM nanoparticles into a polymeric network. Also, some polymers with an active group such as polyacrylamide (PAM), poly­(vinyl pyrrolidone) (PVP), poly­(vinyl alcohol) (PVA), , poly­(ethylene glycol) (PEG), and polyaniline (PAN) have been successfully applied to synthesize the special structure. However, owing to their functional group and poor electron transfer properties, the photochromic properties of these materials do not seem excellent.…”