Stimuli-Sensitive Polymers

Stimuli-sensitive polymers which can respond to certain external environmental changes (Stimulus) by altering properties such as shape, permeability, or color are discussed. The ability of a material to recognize a stimulus and respond to it is derived from stimulisensitive processes on the molecular and/or supramolecular level, as well as on the level of phase morphology, which are translated and amplified to the macroscopic level. The field of stimuli-sensitive polymers is presently progressing rapidly. Besides photochromic molecules, molecules containing thermo labile bonds are investigated as molecular switches in stimuli-sensitive polymers. The most prominent molecular architecture for stimuli-sensitive polymers is entropy-elastic polymer networks, consisting of chemical or physical crosslinks and highly flexible network chains. Stimuli-sensitive polymeric gels are able to swell and shrink in response to certain changes in their environmental conditions such as solvent composition, temperature, light, ionic strength, or pH.