Smart Materials have the ability to change one or more properties when controlled external stimuli

                                                                           

Smart materials 

Smart materials are those that have been manipulated to respond in a controllable and reversible manner, modifying some of their properties in response to external stimuli such as mechanical stress or temperature, among others. Smart materials are also known as responsive materials due to their responsiveness. These are commonly translated as "active" materials, but "reactive" materials would be more accurate.

Smart materials for active coating are primarily active materials that deliver sensing and responding properties to textiles via traditional coating technologies (Singha, 2012). When exposed to a small stimulus, adaptive polymers can undergo significant and noticeable changes. As a result, adaptive coating textiles are preprogrammed to respond to minor environmental changes.

Due to shape-memory alloys, the use of smart materials will allow aircraft wings to be more flexible. The outer elements of an aircraft will become more skin-like in that they must be strong, hard, rigid, and flexible at the same time. The theory behind this design is based on Leonardo da Vinci's flying machine, which is an example of a historic smart material theory being realised with today's modern technology. Because of the introduction of self-healing plastics, the plane's'skin' will also have self-healing properties, even while the aircraft is in flight.

Smart materials are enabling personal protective equipment (PPE) to better respond to user needs, act as global systems, and mitigate the effects of severe environmental conditions. For example, smart-material-based responsive barriers can limit or block the passage of chemical and biologically hazardous species while preserving the majority of the wearer's comfort and functionality. Shape memory polymers, polymer gels, superabsorbent polymers, grafted polymer brushes, and polymeric ionic liquids are among the solutions under consideration for PPE. There are already a few products on the market that use membranes with adjustable breathability.