selfsealing

Self-sealing, sometimes written as selfsealing, refers to a property or design in which a pierced, breached, or damaged component automatically forms a seal without external action. In practice, self-sealing systems rely on internal pressure, embedded sealants, or deformable membranes that respond to disruption by closing the opening and limiting leakage.

Common mechanisms include passive sealing, where elastic layers or membranes close a breach as pressure differentials act; puncture-activated sealants, housed in capsules or bladders, that flow into a hole to block further leakage; and multilayer films or coatings that compress and reseal under load. Materials used may include elastomeric polymers, viscous resins or sealants, microencapsulated polymers, bitumen-based compounds, and hydrophobic films designed to respond to puncture.

Applications span several industries. In aviation and defense, self-sealing fuel tanks are used to reduce fuel loss after projectile puncture, commonly employing bladders and sealant-impregnated layers. Self-sealing tires use internal sealants to rapidly close small punctures as air pressure forces the material into the hole. Other applications include certain packaging, membranes, and piping systems that incorporate self-sealing gaskets or coatings to limit leakage after damage.

Advantages and limitations: self-sealing can reduce leakage, improve safety, and limit damage spread in puncture events. However, effectiveness depends on puncture size and shape, material aging, temperature, and operating pressure. Added weight, cost, and potential long-term performance degradation are considerations in design and maintenance.

See also: self-healing materials, puncture sealing, leak-tight membranes.