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Self-Healing Polymers
Published in Asit Baran Samui, Smart Polymers, 2022
Self-healing materials are substances that can heal any damage caused by any external factors and recover their original properties partially or completely. In nature, some biological materials have the ability to self-repair, such as a cut in the body, bone fracture, etc. However, man-made systems do not have such kind of self-repairing ability. A self-healing property gives materials longer service, particularly in places where accessibility is restricted or places which are prone to damage. The basic idea is to continue the performance of the product as it was before the damage. The possibility of self-healing has propelled the development of a large number of strategies for three categories of materials: metals, ceramics, and polymers. Although many strategies have been developed over the years, the basic requirement remains the same; the generation of a mobile phase in response to damage, which fills the damaged area.1 The temperature of self-healing varies according to the matrix, which increases in the order of concrete< polymers< metals< ceramics
Self-Healing Technology
Published in Ghasan Fahim Huseien, Iman Faridmehr, Mohammad Hajmohammadian Baghban, Self-Healing Cementitious Materials, 2022
Ghasan Fahim Huseien, Iman Faridmehr, Mohammad Hajmohammadian Baghban
From the reviewed studies, the several conclusions can be made: Concrete structure durability and lifespan under different weather conditions are influenced greatly by the high sensitivity of the cement materials to harsh environmental conditions that can cause concrete expansion and eventual cracking.To make the concrete structures more serviceable and expand their use life, crack repair is essential.A material with the self-repair capability is referred to as intelligent or smart material, meaning that it systematically integrates both the construct of information and physical indices like strength and durability, affording the material functionality at a higher level.Different types of materials—such as plastics/polymers, paints/coatings, metals/alloys, and ceramics/concrete—have their own self-healing mechanisms.
Current and Outlook on Manufacturing and Processing Technologies
Published in Yoseph Bar-Cohen, Advances in Manufacturing and Processing of Materials and Structures, 2018
Over time, materials will sustain degradation due to their environmental conditions (e.g., corrosion, ageing) or due to mechanical operation conditions (e.g., fatigue cracking). The damage may be microscopic in size and may change the thermal, electrical, and acoustical properties, which may lead to structural failure. As pointed out earlier, it is essential to monitor the structure health and detect damage and cracks sufficiently early before they reach a critical size that may cause catastrophic failure. The use of self-healing materials protects against degradation by activating a repair mechanism that responds to generated microdamage (Ghosh, 2008). Self-healing materials are artificially/synthetically created substances that are capable of automatically self-repair damage without external diagnosis or human intervention. Composite materials offer the possibility of producing self-healing structures, and this capability has been demonstrated by many researchers (see, for example, Chen et al., 2002). By adding into the material a second phase that consists of an adhesive or toughening agent that is encapsulated in glass microspheres, the structure can reseal itself upon impact by releasing the repair agent.
Focus on self-healing materials: recent challenges and innovations
Published in Science and Technology of Advanced Materials, 2021
Wataru Nakao, Toshio Osada, Tomoya Nishiwaki, Hideyuki Otsuka
One of the material researchers’ dreams is to create artificial materials that have the same functions as natural materials, such as living things. Self-healing material is a material that has a function found in organisms, and naturally exhibits extremely high robust performance. Owing to such a dream function, self-healing materials have been independently researched and developed for each particular material system, such as metal, ceramics, concrete, polymer, and composite material. There is a long history of the research on self-healing materials. For example, self-healing ceramics were first reported in the 1960s. Tracing back with the development of stainless steel to 1904, we would notice that stainless steel could also be considered as one of the self-healing materials, as its oxidation protection layer is spontaneously repaired. Going even further back in history, the first report of self-healing concrete by the precipitation of calcium carbonate can be found as early as 1836.
Thermal analysis on self-healing concrete using polyvinyl alcohol
Published in International Journal of Ambient Energy, 2021
SHC can heal itself from cracks and other minor imperfections and thus prolong the life of the material itself and structure. In plain and reinforced concrete structures, fatigue is one of the major causes of both material and structural failures. Under the moving load due to traffic, it is not only the relatively simple opening and closing action in the transverse direction to the crack plane but also the severe reversed shear displacement along the crack plane. This accelerates the deterioration on the shear transfer mechanism at the crack surface. Although the shear transfer between two cracks accelerates the rupture of crack surface, a lot of crushed powders and fragments are produced in the crack. Cracks in concrete may accelerate the rate of chemical deterioration and reinforcement corrosion that affect the durability of infrastructures. SHC is one of the modern smart concretes which can heal the cracks by itself. These are the results of moisture interaction with unhydrated cement clinker in the crack under some self-healing situations. Self-healing materials are those which can restore nearly or all of its original functionality after being damaged, thus, healed completely or partially.
Alternative Plasma-Facing-Material Concepts for Extreme Plasma-Burning Nuclear Fusion Environments
Published in Fusion Science and Technology, 2019
How does one design in an intelligent way materials that can self-heal? The materials design approach would in essence establish a new class of materials systems for the PMI. These materials can have either self-healing properties, where “self-healing” is defined as materials that freely can repair themselves after damage without any external influence from their environment, or adaptive materials properties.36–38 The term “adaptive” is defined as intrinsic properties coupled to an external influence (e.g., plasma-borne radiation stimulant), whereby during exposure to a defined extreme environment, the material performance is maintained or improved. This paradigm to PMI materials design is transformative in that the design of the PMI is closely coupled with its behavior under well-defined magnetic fusion plasma-edge conditions and studied with robust in situ performance characterization to decipher the dynamic material properties as they evolve during plasma exposure and thus help define the processing schemes to design self-healing or adaptive PFCs.