Shape memory microparticles with permanent shape reconfiguration ability and near infrared light responsiveness

Smart changing microparticles with controllable shapes have attracted considerable attentions due to their potential applications in microactuators, micromotors and biomedical devices. In this work, a shape memory microsphere based on cellulose acetate (CA) was developed by a simple emulsion solvent evaporation method to perform on-demand shape switch under heat stimulus. The morphology of CA microparticles before and after thermal programing were carefully investigated by both optical microscope and scanning electron microscope, demonstrating their excellent microscopic shape memory properties and shape reconfiguring ability as needed. The temporary and permanent shapes of CA microparticles both can be changed arbitrarily by regulating the stretching condition via a film stretching process to meet various requests. Considering the more convenience of near infrared (NIR) light than direct heat for application, the additional NIR light-induced microscopic shape memory performance was realized by the introduction of multi-walled carbon nanotube into CA microspheres, which can further improve their versatile application potential in various fields.