Mechanical force can be used to trigger chemical reactions in a controlled manner. So far chemical reactions were produced with heat, pressure, light and electricity. High frequency sound waves have now been used to initiate chemical reactions in a controlled manner. The test has been carried out for the moment in a chain of polymers created expressly for this purpose, but they think that a new way has been opened to develop applications such as plastics that are repaired alone and new materials that warn with some advance to its breakage.