Elastically and Plastically Foldable Electrothermal Micro‐Origami for Controllable and Rapid Shape Morphing

Fabrication Techniques for Curved Electronics on Arbitrary Surfaces

Soft electrical actuators driven by low voltages are promising for interactive human–machine interfaces (iHMI) applications including executing orders to complete various tasks and communicating with humans. The attractive features of low‐voltage soft electrical actuators include their good safety, low power consumption, small system size, and nonrigid or deformable characteristics. This review covers three typical classes of electrical actuators, namely, electrochemical, electrothermal, and other electrical (dielectric, electrostatic, ferroelectric, and plasticized gel) actuators according to their mechanism and working potential range. For each kind of actuators, the advantages, working principle, device configuration/design, materials selection, recent progress, and potential applications for iHMI are summarized, with the strategies for enhancing the actuation performance under low voltages being highlighted. Finally, the challenges for those soft actuators and possible solutions are discussed.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/aisy.202100075

Low-Voltage Soft Actuators for Interactive Human–Machine Interfaces

https://iopscience.iop.org/article/10.1088/1361-6439/ac1eed/pdf

Terahertz MEMS metadevices

The growth and development of optical components and, in particular, the miniaturization of micro-electro-mechanical systems (MEMSs), has motivated and enabled researchers to design smaller and smaller endoscopes. The overarching goal of this work has been to image smaller previously inaccessible luminal organs in real time, at high resolution, in a minimally invasive manner that does not compromise the comfort of the subject, nor introduce additional risk. Thus, an initial diagnosis can be made, or a small precancerous lesion may be detected, in a small-diameter luminal organ that would not have otherwise been possible. Continuous advancement in the field has enabled a wide range of optical scanners. Different scanning techniques, working principles, and the applications of endoscopic scanners are summarized in this review.

https://summit.sfu.ca/system/files/iritems1/20767/applsci-10-06865-v2.pdf

Endoscopic Optical Imaging Technologies and Devices for Medical Purposes: State of the Art

This paper presents a review of electrothermal micro-actuators and applications. Electrothermal micro-actuators have been a significant research interest over the last two decades, and many different designs and applications have been investigated. The electrothermal actuation method offers several advantages when compared with the other types of actuation approaches based on electrostatic and piezoelectric principles. The electrothermal method offers flexibility in the choice of materials, low-cost fabrication, and large displacement capabilities. The three main configurations of electrothermal actuators are discussed: hot-and-cold-arm, chevron, and bimorph types as well as a few other unconventional actuation approaches. Within each type, trends are outlined from the basic concept and design modifications to applications which have been investigated in order to enhance the performance or to overcome the limitations of the previous designs. It provides a grasp of the actuation methodology, design, and fabrication, and the related performance and applications in cell manipulation, micro assembly, and mechanical testing of nanomaterials, Radio Frequency (RF) switches, and optical Micro-Electro-Mechanical Systems (MEMS).

/pdf/review-of-electrothermal-actuators-and-applications-53dccm5e03.pdf

Review of Electrothermal Actuators and Applications

The remarkable properties of liquid crystal elastomers (LCE) for spatially controlled actuation are utilized to perform complex tasks such as to mimic versatile motion of living organisms and cilia in soft robotics. As opposed to the common out‐of‐plane bending in flat LCE films, many planar micro‐electro‐mechanical and microfluidic systems typically operate based on the lateral movement of the functional parts. The challenge of implementing the in‐plane bending of LCE actuators is often associated with the limited capability for miniaturization of the existing techniques, along with the requirement for post‐fabrication assembly. In this paper a method for fabrication of thermally actuated LCE beams for in‐plane bending applications, which is based on direct laser writing and micromolding is reported. Mesogenic alignment is modified near the sidewalls of the channel structures patterned with vertical microgrooves. The method allows monolithic fabrication of LCE‐based microgrippers for micromanipulation and microassembly applications in life sciences and in manufacture of microsystems. It is shown that the photothermally driven microgrippers can perform soft grasping of micro‐objects, providing large gripping strokes with relatively low actuation stimuli. The fabrication method offers more design opportunities for LCE‐based microactuators and a useful route toward realization of gripping and cargo transportation functionality in microrobotics.

Alissa Potekhina

Papers

Review of Electrothermal Actuators and Applications

Liquid Crystal Elastomer Based Thermal Microactuators and Photothermal Microgrippers Using Lateral Bending Beams