Characterization of core-shell microstructure and self-healing performance of electrospun fiber coatings

Abstract

Electrospun fibers are a promising method for encapsulation of reactive agents in selfhealing coatings. Healing is initiated by mechanical damage to the coating causing the fibers to rupture and release their core materials into the damage region. Prior work has demonstrated autonomous healing in coatings containing electrospun fibers, but full characterization of the electrospun fiber microstructure and healing performance of the coating is lacking. In this study, we utilize electrospun fibers containing liquid healing agents to achieve a crosslinking reaction of poly(dimethylsiloxane) (PDMS) to a crosslinking agent poly(diethoxysiloxane) (PDES), initiated by the catalyst dibutyltindilaurate (DBTL), to fill a damaged region and reseal the metal substrate. Fiber morphology is characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and confocal fluorescence microscopy (CFM). Successful delivery of healing agents to the damage region and subsequent crosslinking reaction is observed using SEM and chemically using infrared spectroscopy. The performance of the healed coating is evaluated electrochemically using linear polarization, where the coatings were subjected to a corrosive environment. The self-healing electrospun coating exhibits lower corrosion current than in control cases, resulting in an 88% corrosion inhibition efficiency.

Electrospinning: A Powerful Tool to Improve the Corrosion Resistance of Metallic Surfaces Using Nanofibrous Coatings

“…Work [68] presents the use of coaxial electrospinning for the development of self-healing coatings composed of electrospun core-shell fibres to protect steel. The liquid healing agents are contained in two types of fibres, type A and B.…”

“…PVC/Ceria NPs Aluminium Cyclic potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) [66] PVA@PVDF doped with MBT Q345 carbon steel Scanning Kelvin Probe (SKF) and Electrochemical Impedance Spectroscopy (EIS) [67] PDMS/PDES@PVA DBTL@PVA Carbon steel Linear polarization [68] PVA@(OA+BTA) Carbon steel Electrochemical Impedance Spectroscopy (EIS) [69] Nylon/BTA Copper Electrochemical Impedance Spectroscopy (EIS) [70] PVDF-ZnO Aluminium alloy Tafel polarization curves and Electrochemical Impedance Spectroscopy (EIS) [71] PVC-ZnO Aluminium alloy (AA6061-T6) Tafel polarization curves and pitting corrosion [72] PVC-ZnO PS-ZnO Aluminium alloy (AA6061-T6) Tafel polarization curves and pitting corrosion [73] CA nanofibres and HAP/CHI solution by dip-coating 304 stainless steel Electrochemical polarization curves and electrochemical impedance [77] PCL and epoxy resin by spin-coating Carbon steel Linear sweep voltammetry [78] TPOZ+GPTMS and PVA doped with Ce(NO 3 ) 3…”

Silicone/Ag@SiO2core–shell nanocomposite as a self-cleaning antifouling coating material

“…12 They are potentially used in various elds including antibacterial, anticorrosion and environmental applications. 13,14 Several studies have highlighted the anti-fungal, antiviral and antifouling activities of Ag NPs.…”

Design Strategy for Self-Healing Epoxy Coatings

“…Strategies like dispersion of a microencapsulated catalyst and healing agents in the coating matrix [30][31][32], loading the healing agent in a core-shell bead-on-string morphology [33], or blending thermoplastics with polymerization-induced phase separation (PIPS) morphology [34] were reported to achieve self-healing coatings [35]. Although researchers have shown the effectiveness of introducing a secondary phase for self-healing, the impacts of the secondary phase on the engineering performances of the polymer system have rarely been studied [36][37][38][39][40][41]. Therefore, for rational material design it is important to understand the underlying mechanisms by which the secondary phase function (i.e., microstructure to macro properties) and elucidate its effects on system properties.…”