Nanofiber-reinforced soft fluidic micro-actuators

Sinatra, Nina R.; Ranzani, Tommaso; Vlassak, Joost J.; Parker, Kevin Kit; Wood, Robert J.

doi:10.1088/1361-6439/aab373

Cited by 30 publications

(27 citation statements)

References 54 publications

(87 reference statements)

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“…Other fluidic actuators that employ slit‐based motifs harness snap‐through instabilities, as have been reported by Overvelde et al, to reduce volumetric requirements to efficiently realize large scale actuators (Figure 14e) 288. Microactuators have also been prepared by Sinatra et al from slit‐type striations within PDMS/nanofiber composites 323…”

Section: Pneumatics and Hydraulicsmentioning

confidence: 93%

Materials as Machines

2020

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of responsive materials as machines is in robotics. The vision, leadership, and research of Bar-Cohen is seminal in both invigorating and focusing current-day research activities to develop responsive materials [2] and implement [3] them as lightweight, dexterous, and gentle (e.g., soft) robotic elements. In this spirit, this review exhaustively details the materials, the nature of their stimuli-response, and discusses considerations for their implementation in robotic systems and subsystems.Robotics is a well-established but growing field of research. Sustained progress in both performance and functionality continue to be realized in commercial robotic systems largely based on conventional materials and their integration with mechanisms. A recent example is the Atlas robot from Boston Dynamics [4] (Figure 1a). The incorporation of stimuli-responsive materials in robotics has largely focused on component-level demonstrations to extend the performance of a subsystem (such as a hand or gripper).Stimuli-responsive materials, spanning nearly all classes of materials and size scales, are currently subject to widespread examination in corporate, government, and academic research laboratories (Figure 1b-d). [5][6][7] In some cases, these materials have already found widespread commercial implementation in end use and are comparatively mature. The materials and fundamentals of their responses are summarized in Figure 2. Shape memory alloys (SMAs) and ceramic piezoelectric materials are distinctive in that they are hard, stimuli-responsive materials. Deformation of these materials can produce large energy densities due to their inherent stiffness. Electroactive polymers (EAPs) remain a topic of considerable interest, particularly dielectric elastomer actuators (DEAs). Engineered systems are rapidly emerging and enabling performance gains in robotics, largely based on pneumatic or fluidic (such as HASEL [8] actuators) transport processes that localize deformation to generate force or produce motion. Soft materials, such as shape memory polymers (SMPs), hydrogels, and liquid crystalline polymer networks (LCNs) and elastomers (LCEs) may offer distinctive functional performance to robotic systems in allowing local control of deformation without the need for complex interfacing with mechanisms. As will be evident, each of these materials has inherent advantages and performance tradeoffs that must be considered in functional implementations. However, responsive material systems have a common obstacle to widespread use: the performance and Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walk...

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Section: Pneumatics and Hydraulicsmentioning

confidence: 93%

Materials as Machines

2020

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“…A schematic of this mechanical programming method and a resulting cross‐section can be seen in Figure 3A. This strategy is similar to larger scale soft actuators that use fiber reinforcements to program bending motions in pneumatic elastic actuators, as well as similarly scaled devices . To accomplish this, we lightly tack the fibers onto the open mold pins prior to inserting them into the mold form for dip coating.…”

Section: Principles and Fabrication Of Motion Programming Structuresmentioning

confidence: 99%

“…This strategy is similar to larger scale soft actuators that use fiber reinforcements to program bending motions in pneumatic elastic actuators, [20,32] as well as similarly scaled devices. [17,33] To accomplish this, we lightly tack the fibers onto the open mold pins prior to inserting them into the mold form for dip coating. When the open face mold is dip coated or poured over, and the rubber cures on the pins, the fiber is mechanically incorporated into the side wall of the actuator, and releases from the pin when the mold assembly is removed.…”

Section: Actuation Direction Established Via Strain-limiting Fibersmentioning

confidence: 99%

“…Arrays of similar actuators have then been integrated into a five‐fingered microhand . Microfingers have also been fabricated with 2.5D molding that has been augmented to incorporate nanofiber strain‐limiting inclusions, similar to demonstrations of multimaterial actuators at larger scales . As a novel alternative to molding, a microtentacle gripper has been fabricated by dip coating a horizontal rod, using gravity to bias the wall thickness in the rubber coating that was formed around the rod.…”

Section: Introductionmentioning

confidence: 99%

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Mechanically Programmable Dip Molding of High Aspect Ratio Soft Actuator Arrays

Becker

Chen

Wood

2020

Adv Funct Materials

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This work presents multiple methods of creating high aspect ratio fluidic soft actuators that can be formed individually or in large arrays via dip coating. Within this methodology, four strategies are provided to mechanically program the motion of these actuators, including the use of fiber inclusions, gravity, surface tension, and electric fields. The modular nature of this dip coating fabrication technique is inexpensive, easy to modify, and scalable. These techniques are used to demonstrate the fabrication of soft actuators with aspect ratios up to 200:1 and integrated arrays of up to 256 actuators. Furthermore, these methods have the potential to achieve higher aspect ratios and larger array sizes. Operating pressure, curvature, and curling strength tests reveal the design space in which fabrication parameters can be selected to tune the input and output parameters of soft bending actuators. An individual bending actuator made with these methods weighs between 0.15 and 0.5 g, can hold up to 2 N, and can be designed to work in groups to increase curling strength with distributed contact forces. Arrays of these actuators may be useful in atypical grasping and manipulation tasks, fluid manipulation, and locomotion.

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“…Among nanomaterials, nanofibers (NFs) are one‐dimensional materials that are widely used in numerous applications such as batteries, biosensors, tissue scaffolds, soft fluidic micro‐actuators, and stretchable electronics . Other than its versatility in different applications, NFs can be easily fabricated with various methods such as sol‐gel process, spray pyrolysis, hydrothermal, electrochemical deposition, and electrospinning .…”

Section: Introductionmentioning

confidence: 99%

Investigation of physicochemical properties of CuSn‐based PAN nanofibers prepared via electrospinning method

Choi

Park

Kang

et al. 2019

Surface & Interface Analysis

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Copper-tin (CuSn) nanomaterials have been receiving substantial attention due to their excellent thermal, electrical, and optical properties. However, how such properties are affected based on heat treatment temperature and chemical composition of copper and tin is still not very well understood. In this paper, CuSn nanofibers were fabricated by electrospinning a precursor solution of polyacrylonitrile, copper, and tin. Calcination temperatures were selected using thermogravimetric/differential thermal analysis (TG/DTA) and Fourier transform infrared (FT-IR) results. Analytical techniques such as scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS) were employed to investigate the physicochemical properties of the CuSn nanofibers. SEM images and EDS revealed the formation of pores on the nanofibers and high concentrations of tin were in the core, while copper was located on the surface. XRD results confirmed the monoclinic phase of Cu 6 Sn 5 for the CuSn nanofibers because peaks for diffraction angles at 27.6°, 53.4°, and 60.0°were observed. XPS results showed that Cu-C and Sn-C bonds occur at binding energies around 932 and 484 eV, respectively. The work function of the CuSn NF heat treated at 150°C was calculated from the UPS spectra, and the value was 4.19 eV.

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Nanofiber-reinforced soft fluidic micro-actuators

Cited by 30 publications

References 54 publications

Materials as Machines

Materials as Machines

Mechanically Programmable Dip Molding of High Aspect Ratio Soft Actuator Arrays

Investigation of physicochemical properties of CuSn‐based PAN nanofibers prepared via electrospinning method

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