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Abstract Double‐sided microfabrication process on an ultra‐thin silicon film has rarely been attempted due to the challenges in terms of the preparation and handling of a thin film in spite of its promising fabrication potentials. Such a process allows for doubling the thin film device density or providing dual functionalities for a thin film depending on whether the front and back sides of a thin film are processed identically or distinctively. Here, a novel double‐sided thin film processing strategy is introduced by realizing a dual coil patterned ultra‐thin silicon film that is working as an actuating or energy harvesting system. Experimentally, a dual coil patterned thin film enabled using the introduced approach shows remarkably enhanced device performance when compared with a single coil patterned counterpart. Furthermore, a multiphysics simulation model is developed and the resultant modeling data validate the experimentally measured performance enhancement. Finally, the structural durability of the thin film upon cyclic loading is tested and its diverse vibration modes are investigated. 

Abstract Direct transfer of pre-patterned device-grade nano-to-microscale materials highly benefits many existing and potential, high performance, heterogeneously integrated functional systems over conventional lithography-based microfabrication. We present, in combined theory and experiment, a self-delamination-driven pattern transfer of a single crystalline silicon thin membrane via well-controlled interfacial design in liquid media. This pattern transfer allows the usage of an intermediate or mediator substrate where both front and back sides of a thin membrane are capable of being integrated with standard lithographical processing, thereby achieving deterministic assembly of the thin membrane into a multi-functional system. Implementations of these capabilities are demonstrated in broad variety of applications ranging from electronics to microelectromechanical systems, wetting and filtration, and metamaterials. 

A shape memory polymer (SMP) has been intensively researched in terms of its exceptional reversible dry adhesive characteristics and related smart adhesive applications over the last decade. However, its unique adhesive properties have rarely been taken into account for other potential applications, such as robotic pick-and-place, which might otherwise improve robotic manipulation and contribute to the related fields. This work explores the use of an SMP to design an adhesive gripper that picks and places a target solid object employing the reversible dry adhesion of an SMP. The numerical and experimental results reveal that an ideal compositional and topological SMP adhesive design can significantly improve its adhesion strength and reversibility, leading to a strong grip force and a minimal release force. Next, a radially averaged power spectrum density (RAPSD) analysis proves that active heating and cooling with a thermoelectric Peltier module (TEC) substantially enhances the conformal adhesive contact of an SMP. Based on these findings, an adhesive gripper is designed, fabricated, and tested. Remarkably, the SMP adhesive gripper interacts not only with flat and smooth dry surfaces, but also moderately rough and even wet surfaces for pick-and-place, showing high adhesion strength (>2 standard atmospheres) which is comparable to or exceeds those of other single-surface contact grippers, such as vacuum, electromagnetic, electroadhesion, and gecko grippers. Lastly, the versatility and utility of the SMP adhesive gripper are highlighted through diverse pick-and-place demonstrations. Associated studies on physical mechanisms, SMP adhesive mechanics, and thermal conditions are also presented. 

A water droplet dispensed on a superhydrophobic ratchet surface is formed into an asymmetric shape, which creates a Laplace pressure gradient due to the contact angle difference between two sides. This work presents a magnetically actuated superhydrophobic ratchet surface composed of nanostructured black silicon strips on elastomer ridges. Uniformly magnetized NdFeB layers sputtered under the black silicon strips enable an external magnetic field to tilt the black silicon strips and form a superhydrophobic ratchet surface. Due to the dynamically controllable Laplace pressure gradient, a water droplet on the reported ratchet surface experiences different forces on two sides, which are explored in this work. Here, the detailed fabrication procedure and the related magnetomechanical model are provided. In addition, the resultant asymmetric spreading of a water droplet is studied. Finally, droplet impact characteristics are investigated in three different behaviors of deposition, rebound, and penetration depending on the impact speed. The findings in this work are exploitable for further droplet manipulation studies based on a dynamically controllable superhydrophobic ratchet surface.