Multifunctional Droplet Manipulation of Heterogeneous Structures using Magnetic Responsive Shape Memory Ridge Arrays and Superhydrophobic Silicon Thin Film

The manipulation of droplets finds applications across diverse fields such as materials synthesis, healthcare, and chemistry. Traditional methods for droplet manipulation involve techniques such as electrowetting and fluidic-based platforms. In this study, we propose a novel approach to induce multifunctional droplet manipulation by utilizing nanostructured superhydrophobic silicon thin films integrated on magnetic particle-embedded SMP (Shape Memory Polymer) ridge arrays. Our approach capitalizes on the inherent Laplace pressure gradient resulting from the interaction between a created heterogeneous structure's ratchet surface and the droplet, overcoming challenges like biofouling associated with externally applied forces. The incorporation of SMP introduces elastic properties, while the silicon thin film contributes superhydrophobicity, optimizing both mechanical characteristics and hydrophobicity of overall platform.<br/><br/>Our choice of SMP is deliberate, as it allows for diverse functionalities through controlled magnetic torque. Unlike traditional magnetic responsive polymers, we employ SMP to perform various functions with partial heating and cooling of the platform. The heterogeneous structure comprising SMP exhibits shape fixing without the need for continuous external stimuli, enhancing energy efficiency.<br/><br/>We believe that this heterogeneous structure, exploiting Laplace pressure gradient, holds promise for applications beyond our study, extending to fields such as digital microfluidics, potentially impacting technologies like lab-on-a-chip devices. The unique combination of SMP and superhydrophobic silicon thin film offers a versatile and energy-efficient platform for advanced droplet manipulation.