3D printed reversible shape changing soft actuators assisted by liquid crystal elastomers

Soft Matter ◽  
2017 ◽  
Vol 13 (33) ◽  
pp. 5558-5568 ◽  
Author(s):  
Chao Yuan ◽  
Devin J. Roach ◽  
Conner K. Dunn ◽  
Quanyi Mu ◽  
Xiao Kuang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
3D Printing ◽  
3D Printed ◽  
Liquid Crystal Elastomers ◽  
Soft Actuators

We fabricate reversible shape changing soft actuators based on the hybrid 3D printing concept.

scholarly journals Synchrotron Microbeam Diffraction Studies on the Alignment within 3D-Printed Smectic-A Liquid Crystal Elastomer Filaments during Extrusion

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 523
Author(s):  
Marianne E. Prévôt ◽  
Senay Ustunel ◽  
Benjamin M. Yavitt ◽  
Guillaume Freychet ◽  
Caitlyn R. Webb ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
3D Printing ◽  
Internal Structure ◽  
Smart Materials ◽  
Time Resolved ◽  
Promote Cell Proliferation ◽  
Liquid Crystal Elastomer ◽  
Smectic A ◽  
3D Printed ◽  
Liquid Crystal Elastomers

3D printing of novel and smart materials has received considerable attention due to its applications within biological and medical fields, mostly as they can be used to print complex architectures and particular designs. However, the internal structure during 3D printing can be problematic to resolve. We present here how time-resolved synchrotron microbeam Small-Angle X-ray Diffraction (μ-SAXD) allows us to elucidate the local orientational structure of a liquid crystal elastomer-based printed scaffold. Most reported 3D-printed liquid crystal elastomers are mainly nematic; here, we present a Smectic-A 3D-printed liquid crystal elastomer that has previously been reported to promote cell proliferation and alignment. The data obtained on the 3D-printed filaments will provide insights into the internal structure of the liquid crystal elastomer for the future fabrication of liquid crystal elastomers as responsive and anisotropic 3D cell scaffolds.

Thermomechanically active electrodes power work-dense soft actuators

Soft Matter ◽  
2021 ◽  
Author(s):  
Angel Martinez ◽  
Arul Clement ◽  
Junfeng Gao ◽  
Julia Kocherzat ◽  
Mohsen Tabrizi ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Metal ◽  
Chain Extender ◽  
Design Work ◽  
Liquid Crystal Elastomers ◽  
Soft Actuators ◽  
Dense Liquid

The effect of chain extender structure and composition on the properties of liquid crystal elastomers (LCE) is presented. Compositions are optimized to design work-dense liquid metal LCE composites that are operated with 100 mW power.

scholarly journals Control-Oriented Modelling of a 3D-Printed Soft Actuator

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 71 ◽  
Author(s):  
Ali Zolfagharian ◽  
Akif Kaynak ◽  
Sui Yang Khoo ◽  
Jun Zhang ◽  
Saeid Nahavandi ◽  
...  
Keyword(s):  
3D Printing ◽  
Dynamic Models ◽  
Three Dimensional ◽  
Input Voltage ◽  
Soft Actuator ◽  
Voltage Variation ◽  
Sophisticated Model ◽  
3D Printed ◽  
Rc Circuit ◽  
Soft Actuators

A new type of soft actuator was developed by using hydrogel materials and three-dimensional (3D) printing technology, attracting the attention of researchers in the soft robotics field. Due to parametric uncertainties of such actuators, which originate in both a custom design nature of 3D printing as well as time and voltage variant characteristics of polyelectrolyte actuators, a sophisticated model to estimate their behaviour is required. This paper presents a practical modeling approach for the deflection of a 3D printed soft actuator. The suggested model is composed of electrical and mechanical dynamic models while the earlier version describes the actuator as a resistive-capacitive (RC) circuit. The latter model relates the ionic charges to the bending of an actuator. The experimental results were acquired to estimate the transfer function parameters of the developed model incorporating Takagi-Sugeno (T-S) fuzzy sets. The proposed model was successful in estimating the end-point trajectory of the actuator, especially in response to a broad range of input voltage variation. With some modifications in the electromechanical aspects of the model, the proposed modelling method can be used with other 3D printed soft actuators.

Simulation and Validation of Fully 3D Printed Soft Actuators

2020 ◽  
Author(s):  
Steffi Torres ◽  
Julio San Martin ◽  
Brittany Newell ◽  
Jose Garcia
Keyword(s):  
3D Printing ◽  
Thermoplastic Polyurethane ◽  
Pharmaceutical Products ◽  
Element Analysis ◽  
Strain Behavior ◽  
Fea Model ◽  
First Case ◽  
3D Printed ◽  
Soft Actuators ◽  
Robotic Applications

Abstract Flexible actuators are a growing class of devices implemented in soft robotic applications, medical devices and processes involving food and pharmaceutical products. Such actuators have traditionally been manufactured using casting processes or other conventional methods requiring more than one fabrication step. The arrival of flexible 3D printing materials and 3D printing techniques has facilitated the creation of these flexible actuators via additive manufacturing. The work presented in this article displays the analytical characterization and experimental validation of two materials and two actuator designs. The first case presents a finite element analysis (FEA) simulated model of a bellows actuator using a photocurable flexible resin (TangoPlus FLX930) and studies the effect of printing orientation on the simulation. The simulation used a 5 parameter Mooney-Rivlin model to predict the strain behavior of the actuator under hydrostatic pressure. A second case is presented where a Thermoplastic Polyurethane actuator was 3D printed and simulated using the same FEA model and a second calibration of the Mooney-Rivlin 5 parameter model. In both cases experimental data was used to calibrate and validate the simulation. The resulting simulated strain was consistent when the printing orientation of actuators was parallel (0 degrees) to the strain direction of the actuators. Results were less consistent when a print orientation of 45 degrees was applied.

scholarly journals Soft actuators using liquid crystal elastomers with encapsulated liquid metal joule heaters

2020 ◽  
Vol 3 (2) ◽  
pp. 025003 ◽  
Author(s):  
Teresa A Kent ◽  
Michael J Ford ◽  
Eric J Markvicka ◽  
Carmel Majidi
Keyword(s):  
Liquid Crystal ◽  
Liquid Metal ◽  
Liquid Crystal Elastomers ◽  
Soft Actuators

scholarly journals Powering and Fabrication of Small-Scale Robotics Systems

2021 ◽  
Author(s):  
Salvador Pané ◽  
Pedro Wendel-Garcia ◽  
Yonca Belce ◽  
Xiang-Zhong Chen ◽  
Josep Puigmartí-Luis
Keyword(s):  
Liquid Crystal ◽  
3D Printing ◽  
Magnetic Fields ◽  
Chemical Synthesis ◽  
Material Science ◽  
Biomedical Applications ◽  
Process Engineering ◽  
Small Scale ◽  
The World ◽  
Liquid Crystal Elastomers

Abstract Purpose of Review The increasing number of contributions in the field of small-scale robotics is significantly associated with the progress in material science and process engineering during the last half century. With the objective of integrating the most optimal materials for the propulsion of these motile micro- and nanosystems, several manufacturing strategies have been adopted or specifically developed. This brief review covers some recent advances in materials and fabrication of small-scale robots with a focus on the materials serving as components for their motion and actuation. Recent Findings Integration of a wealth of materials is now possible in several micro- and nanorobotic designs owing to the advances in micro- and nanofabrication and chemical synthesis. Regarding light-driven swimmers, novel photocatalytic materials and deformable liquid crystal elastomers have been recently reported. Acoustic swimmers are also gaining attention, with several prominent examples of acoustic bubble-based 3D swimmers being recently reported. Magnetic micro- and nanorobots are increasingly investigated for their prospective use in biomedical applications. The adoption of different materials and novel fabrication strategies based on 3D printing, template-assisted electrodeposition, or electrospinning is briefly discussed. Summary A brief review on fabrication and powering of small-scale robotics is presented. First, a concise introduction to the world of small-scale robotics and their propulsion by means of magnetic fields, ultrasound, and light is provided. Recent examples of materials and fabrication methodologies for the realization of these devices follow thereafter.

scholarly journals Monolithic shape-programmable dielectric liquid crystal elastomer actuators

2019 ◽  
Vol 5 (11) ◽  
pp. eaay0855 ◽  
Author(s):  
Zoey S. Davidson ◽  
Hamed Shahsavan ◽  
Amirreza Aghakhani ◽  
Yubing Guo ◽  
Lindsey Hines ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
High Performance ◽  
Degrees Of Freedom ◽  
New Technologies ◽  
Elastic Anisotropy ◽  
Active Material ◽  
Soft Robotics ◽  
Liquid Crystal Elastomer ◽  
Liquid Crystal Elastomers ◽  
Soft Actuators

Soft robotics may enable many new technologies in which humans and robots physically interact, yet the necessary high-performance soft actuators still do not exist. The optimal soft actuators need to be fast and forceful and have programmable shape changes. Furthermore, they should be energy efficient for untethered applications and easy to fabricate. Here, we combine desirable characteristics from two distinct active material systems: fast and highly efficient actuation from dielectric elastomers and directed shape programmability from liquid crystal elastomers. Via a top-down photoalignment method, we program molecular alignment and localized giant elastic anisotropy into the liquid crystal elastomers. The linearly actuated liquid crystal elastomer monoliths achieve strain rates over 120% per second with an energy conversion efficiency of 20% while moving loads over 700 times the elastomer weight. The electric actuation mechanism offers unprecedented opportunities toward miniaturization with shape programmability, efficiency, and more degrees of freedom for applications in soft robotics and beyond.

scholarly journals Soft elasticity optimises dissipation in 3D-printed liquid crystal elastomers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
D. Mistry ◽  
N. A. Traugutt ◽  
B. Sanborn ◽  
R. H. Volpe ◽  
L. S. Chatham ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Strain Energy ◽  
Severity Index ◽  
Strain Rates ◽  
Direct Ink Writing ◽  
Buckling Behavior ◽  
3D Printed ◽  
Soft Elasticity ◽  
Liquid Crystal Elastomers ◽  
Director Orientation

AbstractSoft-elasticity in monodomain liquid crystal elastomers (LCEs) is promising for impact-absorbing applications where strain energy is ideally absorbed at constant stress. Conventionally, compressive and impact studies on LCEs have not been performed given the notorious difficulty synthesizing sufficiently large monodomain devices. Here, we use direct-ink writing 3D printing to fabricate bulk (>cm3) monodomain LCE devices and study their compressive soft-elasticity over 8 decades of strain rate. At quasi-static rates, the monodomain soft-elastic LCE dissipated 45% of strain energy while comparator materials dissipated less than 20%. At strain rates up to 3000 s−1, our soft-elastic monodomain LCE consistently performed closest to an ideal-impact absorber. Drop testing reveals soft-elasticity as a likely mechanism for effectively reducing the severity of impacts – with soft elastic LCEs offering a Gadd Severity Index 40% lower than a comparable isotropic elastomer. Lastly, we demonstrate tailoring deformation and buckling behavior in monodomain LCEs via the printed director orientation.

scholarly journals Effect of Isomeric Amine Chain Extenders and Crosslink Density on the Properties of Liquid Crystal Elastomers

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3094
Author(s):  
Yoojin Lee ◽  
Subi Choi ◽  
Beom-Goo Kang ◽  
Suk-kyun Ahn
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystal ◽  
Molecular Engineering ◽  
Side Chain ◽  
Aerospace Medicine ◽  
Different Types ◽  
Chain Extenders ◽  
Liquid Crystal Elastomers ◽  
Soft Actuators ◽  
Significant Attention

Among the various types of shape changing materials, liquid crystal elastomers (LCEs) have received significant attention as they can undergo programmed and reversible shape transformations. The molecular engineering of LCEs is the key to manipulating their phase transition, mechanical properties, and actuation performance. In this work, LCEs containing three different types of butyl groups (n-, iso-, and sec-butyl) in the side chain were synthesized, and the effect of isomeric amine chain extenders on the thermal, mechanical, and actuation properties of the resulting LCEs was investigated. Because of the considerably low reactivity of the sec-butyl group toward the diacrylate in the LC monomer, only a densely crosslinked LCE was synthesized. Most interestingly, the mechanical properties, actuation temperature, and blocking stress of the LCEs comprising isobutyl groups were higher than those of the LCEs comprising n-butyl groups. This difference was attributed to the presence of branches in the LCEs with isobutyl groups, which resulted in a tighter molecular packing and reduced the free volume. Our results suggest a facile and effective method for synthesizing LCEs with tailored mechanical and actuation properties by the choice of chain extenders, which may advance the development of soft actuators for a variety of applications in aerospace, medicine, and optics.

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