MECHANICS OF INNOVATIVE RESPONSIVE POLYMERS

The study of responsive structural systems and materials, whose main aim is the development of so-called smart devices capable of autonomously respond to external stimuli with some desired de- tectable reaction, is nowadays a very attractive research field. The external stimulus can have a chemical (pH, …), physical (light, temperature, …) or mechanical nature (stress). Within this modern research con- text, the development of materials capable to react at the molecular level is quite attractive, and provides the potentiality to get a response at the meso- or macro-scale level through the sum of the micro-level responses of the constituting molecules. This capability can be easily obtained in polymers and polymer- like materials by properly introducing responsive molecules in their network. In the present paper, the mechanics of polymers with embedded active (or responsive) molecules is developed starting from the physics of the mechanisms taking place at the molecular level. The micromechanical framework is illus- trated starting from the behavior of the polymer matrix, and then by considering the effect of respon- sive molecules when their activation entails a change of their geometrical size and/or conformation. The mechanical stress arising in the responsive polymer is thus determined and, finally, some examples are illustrated to demonstrate the capability of the developed approach as a tool for the design of smart polymers having desired functionalities.