Scientists at US Naval Research Laboratory (NRL) have developed a transparent thermoplastic elastomer armor to reduce weight. Thermoplastic elastomers (TPEs) are soft and rubbery polymers that can be converted to a solid by physical means instead of a chemical process. Hence, the solidification is reversible, and facilitates the repair of damaged armour surfaces ‘on-the-fly’ in the field. NRL Soft Matter Physics senior scientist Dr Mike Roland said: "Heating the material above the softening point of around 100 degrees Celsius melts the small crystallites, enabling the fracture surfaces to meld together and reform via diffusion. This can be accomplished with a hot plate, akin to an iron, that moulds the newly forming surface into a smooth, flat sheet with negligible effect on integrity," said Dr. Mike Roland, senior scientist, NRL Soft Matter Physics. NRL researchers have so far tested the use of polymeric materials as a coating to attain enhanced impact resistance of hard substrates. The application of polyurea and polyisobutylene layers can improve the ballistic performance of armour and helmets, and obtain improved ballistic effectiveness and mitigation of blast waves. NRL researchers are also able to recreate superior ballistic properties of polyurea and polyisobutylene coatings by using TPEs, with the advantages of the material being lighter than conventional bullet-resistant glass, transparent and easily repairable. "Because of the dissipative properties of the elastomer, the damage due to a projectile strike is limited to the impact locus. This means that the effect on visibility is almost inconsequential, and multi-hit protection is achieved," added Roland. The transparent thermoplastic elastomer armor technology of NRL is covered by US Patent #9,285,191; "Polymer Coatings for Enhanced and Field-Repairable Transparent Armour."