Design, fabrication, and application of stimuli-responsive hydrogel actuators

Abstract

In this thesis, the topics around hydrogel based stimuli-responsive actuators were discussed. In each project, a specially designed stimuli-responsive hydrogel was fabricated. By initiating a corresponding stimuli, swell-deswell changes will be triggered within the hydrogels, and certain mechanical movements can be created by manipulating the patterns and structures of the hydrogels. Stimuli-responsive hydrogels often exhibit sharp volume phase transitions triggered by specific chemical or physical stimuli. Volume phase transitions has been vastly studied due to its potential in triggering the functions of movements, such as deformation 1 , volume change 2 , modulus change 3 , force generation 4 etc., are similar to biological systems in the nature. And there are numerous methods to trigger these responses, such as pH value 5 , electric field 6 , ion concentration 7 , chemical or biological reagents 8 etc. Based on the capability of chemomechanical energy conversion, stimuli-responsive polymers have a broad range of applications, ranging from mechanical actuators 9 , soft robotics 1 . We aimed at the designs and applications biomimetic actuators and soft robotics. Among the five projects will be discussed in this thesis, the first three systems are chemically initiated stimuli responsive actuators (chemomechanical actuators); the other two systems are non-chemically initiated.