A brief review of stimulus-active polymers responsive to thermal, light, magnetic, electric, and water/solvent stimuli

Stimulus-active polymers can vary their shapes (configuration or dimension) or produce mechanical power in response to external stimuli such as heat, electricity, light, magnetic field, and water. In the past decade, many breakthroughs have been made in developing stimulus-active polymers with novel stimulus-active mechanisms. With proper designing, complicated movements such as swimming, inchworm walking, rotation, and bending can be achieved. Stimulus-active polymers can be applied in a wide range of areas from hi-tech areas to daily life. A few papers have been written on specific type of stimulus-active polymers, but have not covered all stimulus-active polymers. Hence, this article aims to present a brief overview of the different mechanisms and fabrication strategies of typical stimulus-active polymers. The various applications of different stimulus-active polymers are also briefly summarized in the article.