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This paper aims to focus on the research progress of intelligent self-healing anti-corrosion coatings in the aviation field in the past few years. The paper provides certain literature review supports and development direction suggestions for future research on intelligent self-healing coatings in aviation.

This mini-review uses a systematic literature review process to provide a comprehensive and up-to-date review of intelligent self-healing anti-corrosion coatings that have been researched and applied in the field of aviation in recent years. In total, 64 articles published in journals in this field in the last few years were analysed in this paper.

The authors conclude that the incorporation of multiple external stimulus-response mechanisms makes the coatings smarter in addition to their original self-healing corrosion protection function. In the future, further research is still needed in the research and development of new coating materials, the synergistic release of multiple self-healing mechanisms, coating preparation technology and corrosion monitoring technology.

To the best of the authors’ knowledge, this is one of the few systematic literature reviews on intelligent self-healing anti-corrosion coatings in aviation. The authors provide a comprehensive overview of the topical issues of such coatings and present their views and opinions by discussing the opportunities and challenges that self-healing coatings will face in future development.

The purpose of this paper is to add expanded perlite (EP) immobilized microorganisms that replace part of the standard sand in mortar to improve the self-healing ability of mortar cracks and reduce the water absorption of mortar after healing.

Bacillus pseudofirmus spores were immobilized with EP particles as self-healing agents. The effects of adding self-healing agents on the compressive strength of mortar specimens were observed. The ability of mortar specimens to heal cracks was evaluated using crack microscopic observation and water absorption experiments. The filler at the cracks was microscopically analyzed by scanning electron microscope and X-ray diffraction experiments.

First, the internal curing effect of EP promotes the hydration of cement in mortar, which generates more amount and denser crystal structure of Ca(OH)2 at mortar cracks and improves the self-healing ability of mortar. Second, the self-healing ability of mortar improves with the increase of self-healing agent admixture. Adding a self-healing agent of high admixture makes the planar undulation of calcite crystal accumulation at mortar cracks more significant. Finally, the initial crack widths that can be completely healed by adding EP and self-healing agents to the mortar are 200 µm and 600 µm, respectively.

The innovation points of this study are as follows. (1) The mechanism of the internal curing effect of EP particles on the self-healing ability of mortar cracks was revealed by crack microscopic observation tests and microscopic experiments. (2) The effect of different self-healing agent amounts on the self-healing ability of mortar cracks has been studied. (3) The effects of EP particles and self-healing agents on healing different initial widths were elucidated by crack microscopic observation tests.

Polyaniline (PANI) has garnered attention for its potential applications in anticorrosion fields because of its unique properties. Satisfactory outcomes have been achieved when using PANI as a functional filler in organic coatings. More recently, research has extensively explored PANI-based organic coatings with self-healing properties. The purpose of this paper is to provide a summary of the active agents, methods and mechanisms involved in the self-healing of organic coatings.

This study uses specific doped acids and metal corrosion inhibitors as active and self-healing agents to modify PANI using the methods of oxidation polymerization, template synthesis, nanosheet carrier and nanocontainer loading methods. The anticorrosion performance of the coatings is evaluated using EIS, LEIS and salt spray tests.

Specific doped acids and metal corrosion inhibitors are used as active agents to modify PANI and confer self-healing properties to the coatings. The coatings’ active protection mechanism encompasses PANI’s own passivation ability, the adsorption of active agents and the creation of insoluble compounds or complexes.

This paper summarizes the active agents used to modify PANI, the procedures used for modification and the self-healing mechanism of the composite coatings. It also proposes future directions for developing PANI organic coatings with self-healing capabilities. The summaries and proposals presented may facilitate large-scale production of the PANI organic coatings, which exhibit outstanding anticorrosion competence and self-healing properties.

This study aims to develop a polymer cement-based waterproof coating with self-healing capability to efficiently and intelligently solve the building leakage caused by cracking of waterproof materials, along with excellent durability to prolong its service life.

Ion chelators are introduced into the composite system based on ethylene vinyl acetate copolymer emulsion and ordinary Portland cement to prepare self-healing polymer cement-based waterproof coating. Hydration, microstructure, wettability, mechanical properties, durability, self-healing performance and self-healing products of polymer cement-based waterproof coating with ion chelator are investigated systematically. Meanwhile, the chemical composition of self-healing products in the crack was examined.

The results showed that ion chelators could motivate the hydration of C₂S and C₃S, as well as the formation of hydration products (C-S-H gel) of the waterproof coating to improve its compactness. Compared with the control group, the waterproof coating with ion chelator had more excellent water resistance, alkali resistance, thermal and UV aging resistance. When the dosage of ion chelator was 2%, after 28 days of curing, cracks with a width of 0.29 mm in waterproof coating could fully heal and cracks with a width of 0.50 mm could achieve a self-healing efficiency of 72%. Furthermore, the results reveal that the self-healing product in the crack was calcite crystalline CaCO₃.

A novel ion chelator was introduced into the composite coating system to endow it with excellent self-healing ability to prolong its service life. It has huge application potential in the field of building waterproofing.

Self-healing concrete is a revolutionary building material that will generally reduce the maintenance cost of concrete constructions. Self-healing of cracks in concrete structure would contribute to a longer service life of the concrete and would make the material more durable and more sustainable. The cementitious mortar with/without incorporating encapsulates at different percentages of slag replacement with the cement mix improves autogenous healing at different ages. Therefore, this study’s aim is to develop a self-healing cementitious matrix for repair and retrofitting of concrete structures.

In the present work, waste straw pipes are used as a capsule, filled with the solution of sodium hydroxide (NaOH), sodium silicate (Na₂SiO₃) and colloidal nano-silica as self-healing activators. An artificial micro-crack on the control and blended mortar specimens at different percentages of slag replacement with cement (with/without encapsulation) is developed by applying a compressive load of 50% of its ultimate load-carrying capacity. The mechanical strength and ultrasonic pulse velocity, water absorption and chloride ion penetration test are conducted on the concrete specimen before and after the healing period. Finally, the self-healing activity of mortar mixes with/without encapsulation is analysed at different ages.

The encapsulated mortar mix with 10% of slag content has better self-healing potential than all other mixes considering mechanical strength and durability. The enhancement of the self-healing potential of such mortar mix is mainly due to hydration of anhydrous slag on the crack surface and transformation of amorphous slag to the crystalline phase in presence of encapsulated fluid.

The self-healing activities of the slag-based cementitious composite are studied for a healing period of 90 days only. The strength and durability performance of the cracked specimen may be increased after a long healing period.

The outcome of the work will help repair the cracks in the concrete structure and enhances the service life.

This study identifies the addition encapsulates with a self-healing activator fluid that can recover its strength after minor damage.

The aim of this work is to investigate the self-healing performance of epoxy coatings containing microcapsules. The microcapsule-based coatings were applied on AA6061 Al alloy and immersed in 3.5 per cent NaCl solution.

Microcapsules with urea–formaldehyde as the shell and linseed oil as the healing agent were prepared by in situ polymerization in an oil-in-water emulsion. For the sake of an optimum self-healing system, some coating samples were prepared by using different microcapsule concentrations: 0, 5, 10 and 20 Wt.%. The scratch-filling efficiency as the theoretical estimate of the self-healing performance was calculated for the coating samples with different microcapsule concentrations. The scratch-sealing efficiency (SSE) as a particularly crucial parameter in the self-healing evaluation of coatings was measured by both electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques.

According to EIS and EN results, the coating samples containing 5 and 10 per cent microcapsules provided the insignificant self-healing performance, while the coating sample containing 20 per cent microcapsules exhibited the acceptable self-healing performance to AA6061 alloy in the NaCl solution. The measured SSE values confirmed the good agreement of EN data with electrochemical parameters obtained from the EIS technique.

This work is an attempt to evaluate the self-healing performance of microcapsule-based epoxy coatings applied on AA6061 Al alloy in sea water.

In this study, the focus was shifted from repairing durable goods to achieving healthier ecology, making durable goods more secure in turn. This study introduced preventive maintenance behavior to trace the ex-post control of “curling” back to the ex-post control of “self-healing.” This study tries to close the gap between the human repair of machines and their “self-curing.” Finally, the author makes the machines healthier.

The paper constructed a mathematical model of preventive maintenance behavior during a specific period for durable consumer goods. The author builds a simulation function of the two-stage preventative maintenance behavior relations. The study used simulations to analyze the influencing relationship and differences between three preventive maintenance behavior elements to basic warranty preventive maintenance (BWPM) behavior and extended warranty preventive maintenance (EWPM) behavior.

Both BWPM behavior and EWPM behavior were affected by the preventive maintenance (PM) behavioral components in different ways. The influence paths of the two warranty periods affected by PM behavior were also different.

This study introduced PM behavior to trace the ex-post control of “curling” back to the ex-post control of “self-healing.” This study adopted the human–machine interaction mode to improve durable goods' self-healing ability during operation and enable a more effective and sustainable development.

This study’s conclusions may help manufacturers guide PM behavior in a way that achieves “self-healing” of the durable goods.

The author opened a “black box” of PM behaviors and analyzed their components. The internal structure relation of PM behavior is built and the closed-loop system of spatial structure is formed.

The purpose of this work was to prepare a catalyst-free microcapsules as self-healing agent in an automotive clearcoat to improve the scratch resistance of coatings.

In this research, microcapsule with isophorone diisocyanate (IDPI) core and polyurethane shell were prepared and used in self-healing coatings. Microcapsules synthesised were characterised by thermal gravimeter and infrared spectra. The microcapsules were dispersed in an acrylic-melamine clearcoat, and the scratch resistance was evaluated.

The triplex product and the formed polyurethane bonds were confirmed by thermal gravimeter and infrared spectra. In addition, smooth spherical particles with a diameter of 1.5 to 1.7 micronmeters were observed by a scanning electron microscope. The microcapsules dispersed in an acrylic-melamine clearcoat increased the scratch resistance of coatings. Also, the self-healing feature of those coatings was proved.

The size of microcapsules can affect its dispersion in the clearcoat and consequently affect the properties of the cured films.

The self-healing coatings are interested for many industries such as building and automotive industries. The reported data can be used by the formulators working in the R & D departments.

Self-healing systems are considered as one of the smart coatings. Therefore, the developing of its knowledge can help to extend its usage to different applications.

The application of microcapsules in the coating as healing agents is a great challenge, which has been hardly investigated so far. In the current research, the effect of polyurethane-IDPI microcapsules in an automotive clearcoat as a self-healing coating was investigated.

The purpose of this study is the investigation of self-healing materials containing encapsulated healing agents embedded in a polymer matrix with dispersed catalysts. In recent years, the high performance and design flexibility of composite materials have led to their widespread use in the aeronautics, space, automotive and marine fields. Simultaneously, as the need for advanced material properties has increased, many studies have been conducted on multifunctional materials, focusing on different fields of their desired capabilities.

A multiscale model was developed to simulate the effect of microcapsules on the mechanical behavior of the polymer matrix. Furthermore, the effects of microcapsule diameter and microcapsule concentration on the mechanical behavior of the composite were studied. Digimat and Ansys software were used to simulate the self-healing composites.

There is a trade-off between the efficiency of the microcapsules and the degradation of the properties of the composite material.

The generated model simulated an encapsulated healing agent in a polymeric matrix.