Polyaniline Microspheres with Corrosion Inhibition, Corrosion Sensing, and Photothermal Self-Healing Properties toward Intelligent Coating

Abstract

A smart coating integrating functions of corrosion inhibition, self-healing, and corrosion-sensing was developed based on a polyaniline (PANI) microsphere-loading corrosion sensing probe (8-hydroxyquinone, 8-HQ). The PANI microsphere was prepared in a facile one-pot process via the combination of photopolymerization and an emulsion template. The 8-HQ-loaded PANI microsphere achieved three synergetic effects simultaneously: corrosion inhibition, corrosion sensing, and photothermal self-healing abilities. Benefiting from the corrosion inhibition effect of PANI, the coating with the PANI microsphere exhibited significantly enhanced anticorrosion behavior. After soaking in NaCl solution for 35 days, its impedance was maintained at 1.26 × 10 9 Ω•cm 2 , nearly 3 orders of magnitude higher than that of pure resin coating. Meanwhile, the encapsulated 8-HQ exhibited pH-responsive release behavior thanks to the pH-responsive characteristics of PANI, which could chelate with Al 3+ ions to form 8-HQ-Al 3+ coordinates with a conspicuous fluorescence, achieving a real-time corrosion diagnosing function. Moreover, benefiting from the photothermal property of PANI, the coating with the PANI microsphere displayed rapid crack closure behavior under NIR light irradiation, and the healing efficiency could reach 83.56% under near-infrared irradiation. This work presents an innovative strategy for fabricating an intelligent self-healing, self-reporting, and anticorrosion coating, which provides a new vision to prolong the lifetime of metals.

Preparation of Graphene Oxide/Polymer Hybrid Microcapsules via Photopolymerization for Double Self-Healing Anticorrosion Coatings

“…The EIS test was carried out using an electrochemical workstation (Chenhua CHI 660E), in which the frequency range was 10 5 to 10 –1 Hz and the applied voltage perturbation was 0.02 V. The SST test was carried out in a salt spray chamber (Q-Lab, SSP600) according to standard ASTM B117. The healing efficiency of coatings was calculated by integrating the area under the curve of the Bode plots between 10 5 and 10 –1 Hz of the blank coatings and scratched coating after healing using eq . , S e l f ‐ h e a l i n g .25em e f f i c i e n c y .25em ( % ) = ∫ 10 − 1 H z 10 5 H z B o d e .25em p l o t .25em o f .25em t h e .25em c o a t i n g .25em a f t e r .25em h e a l i n g ...…”