Comparative analysis of shape memory‐based self‐healing coatings

Abstract

Self-healing materials exhibit the ability to repair and to recover their functionality upon damage. Here, we report on an investigation into preparation and characterization of shape memory assisted self-healing coatings. We built on past work in which poly(e-caprolactone) electrospun fibers were infiltrated with a shape memory epoxy matrix and delve into fabricating and characterizing a coating with the same materials, but employing a blending approach, polymerization induced phase separation. After applying controlled damage, the ability of both coatings to self-heal upon heating was investigated. In both methods, coatings showed excellent thermally induced crack closure and protection against corrosion, with the blend approach being more suitable for large-scale applications given its process simplicity. Two different approaches to the preparation of shape memory-based selfhealing coatings were compared for their ability to heal structurally and functionally by heating. These two approaches, electrospinning versus polymerization-induced phase separation were found to feature comparable and quite complete healing, with the latter system offering the advantage of facile processing.

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

“…In addition, this type of coating can be implemented onto medical implants, being a promising material for long-term stability in biomedical applications. A novel approach for self-healing applications is found in [78] where poly(caprolactone) (PCL) was electrospun onto metallic substrate and further infiltrated with a shape memory epoxy matrix using a spin coater.…”

“…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…”

Thermoactive Smart Electrospun Nanofibers

“…Yao et al [197] incorporated an electrospun PCL microfiber mesh in an epoxy matrix, both serving as a toughening agent in epoxy and as an internal structure to guide self-healing. In another work, [198] with the aim to provide surface protection towards scratches and corrosion, a Production and self-forming multichannel conduit for nerve guidance and regeneration based on shape memory P(LA-co-TMC) nanofibrous mat: presenting a permanent tubular shape, it may be temporarily fixed in a planar one to achieve a uniform cellular growth; the initial tubular shape can be restored by heating to the human body temperature. Reproduced with permission.…”

“…[ 197 ] incorporated an electrospun PCL microfiber mesh in an epoxy matrix, both serving as a toughening agent in epoxy and as an internal structure to guide self‐healing. In another work, [ 198 ] with the aim to provide surface protection towards scratches and corrosion, a composite coating, consisting of an electrospun PCL was embedded in an epoxy resin. The coating, after the formation of a crack, turned out to be able to repair the crack, upon heating above PCL melting temperature, by not only restoring the physical integrity, but also the initial corrosion resistance.…”

Shape-Memory Materials via Electrospinning: A Review

“…Birjandi et al [78] reported in 2016 the incorporation of PCL electrospun fibers into a shape-memory EP matrix in order to develop a shape memory-based self-healing coating. In particular, shape memory can be used to fabricate self-healing (SH) polymers that are able to close and repair cracks when thermally activated [79].…”