Noncontact All-In-Situ Reversible Reconfiguration of Femtosecond Laser-Induced Shape Memory Magnetic Microcones for Multifunctional Liquid Droplet Manipulation and Information Encryption

摘要

Shape memory polymers can change their shapes in a controlled way under external stimuli and thus promote the development of smart devices, soft robotics, and microfluidics. Here, a kind of iron particles (IPs) doped shape memory microcone is developed for noncontact all-in-situ reversible tuning between the tilted and upright state under near-infrared (NIR) irradiation and magnetic field (MF) actuation. The magnetic microcones are simply fabricated by a laser-ablated replica-molding strategy so that their height can be precisely controlled by adjusting the laser machining parameters. In addition, it is found that the droplets can be transported unidirectionally on the tilted microcones, which is related to the variation of the adhesion force induced by the length of the triple contact line (TCL). Finally, other multifunctional applications have also been realized, such as, selective droplet release, information encryption, rewritable display, and reusable temperature switch. This work may provide a facile strategy for developing multiresponsive smart devices based on shape memory polymers.