Reversible patterning and actuation of hydrogels by electrically assisted ionoprinting

Palleau, Etienne; Morales, Daniel; Dickey, Michael D.; Velev, Orlin D.

doi:10.1038/ncomms3257

Cited by 414 publications

(351 citation statements)

References 30 publications

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“…Soft robots are machines fabricated from compliant materials (polymers [1][2][3][4][5][6][7][8] , elastomers [1] , hydrogels [9,10] , granules [11] ); they can operate with several different modes of actuation (i.e., pneumatic [1,5,[11][12][13] , electrical [7,[14][15][16][17][18] , chemical [12,19,20] ), and their motion can be either fast (>1 Hz) [9,12,14] or slow (<0.1 Hz) [1,21] .…”

Section: Introductionmentioning

confidence: 99%

Pneumatic Networks for Soft Robotics that Actuate Rapidly

Mosadegh

Polygerinos

Keplinger

et al. 2014

Adv Funct Materials

1,305

827

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Soft robots actuated by pressurization and inflation of a pneumatic network (a "pneunet") of small channels in elastomeric materials are appealing for their ability to produce sophisticated motions with simple controls. Although current designs of pneu-nets achieve motion with large amplitudes, they do so relatively slowly (that is, over seconds). This paper describes a new design for pneu-nets that reduces the amount of gas that must be transported for inflation of the pneu-net, and thus increases its speed of actuation. A simple actuator can bend from a linear shape to a quasi-circular shape in 50 milliseconds when pressurized at ΔP = 345 kPa. At high rates of pressurization and inflation, the path along which the actuator bends depends on this rate. When inflated fully, the channels and chambers of this new pneu-net design experience only one-tenth the change in volume of that required for a motion of equal amplitude using the previous design. This small change in volume requires comparably low levels of strain in the material at maximum amplitudes of actuation, and commensurately low rates of fatigue and failure. This actuator can operate over a million cycles without significant degradation of performance. This design for soft robotic actuators combines high rates of actuation with high reliability of the actuator, and opens new areas of application for them.

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Section: Introductionmentioning

confidence: 99%

Pneumatic Networks for Soft Robotics that Actuate Rapidly

Mosadegh

Polygerinos

Keplinger

et al. 2014

Adv Funct Materials

1,305

827

View full text Add to dashboard Cite

show abstract

“…The shape transformations of biological organisms [1][2][3][4][5][6] have been the inspiration for many products in the field of artificial muscles, [7][8][9][10][11][12][13] soft robotics, [14][15][16][17][18][19] sensors 20 and complex shape engineering. 21,22 For example, the leaves of the Venus flytrap snap together to capture insects by virtue of the synergy between the hydroelastic instability and asymmetric expansion of the inner and outer surfaces at the cellular level.…”

Section: Introductionmentioning

confidence: 99%

A monolithic hydro/organo macro copolymer actuator synthesized via interfacial copolymerization

et al. 2017

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Synthetic polymer actuators have attracted increasing attention for their potential applications in artificial muscles, soft robotics and sensors. The majority of previous efforts have focused on smart hydrogels with bilayer structures that can change their shape in response to environmental stimuli, such as temperature, light and certain chemicals. However, the practical application of hydrogels is limited because of their low modulus and weak mechanical strength. Here we synthesized a robust monolithic actuator of a macro-scale hydro/organo binary cooperative Janus copolymer film. The process involves direct, one-step interfacial polymerization of immiscible hydrophilic and hydrophobic vinyl monomer solutions, and the resultant product exhibited binary cooperative shape transformation to multiple external stimuli. The Janus copolymer film can work in both aqueous solutions and organic solvents, with bidirectional and site-specific bending arising from cooperative asymmetric swelling/shrinking of the hydrogel and organogel networks. In addition, the as-prepared Janus copolymer film can act as a sensor element for solvent leakage detection. This binary cooperative strategy is applicable to most immiscible monomer systems and provides a general approach to developing novel functional copolymer materials. NPG Asia Materials (2017) 9, e380; doi:10.1038/am.2017.61; published online 19 May 2017 INTRODUCTIONThe shape transformations of biological organisms [1][2][3][4][5][6] have been the inspiration for many products in the field of artificial muscles, 7-13 soft robotics, 14-19 sensors 20 and complex shape engineering. 21,22 For example, the leaves of the Venus flytrap snap together to capture insects by virtue of the synergy between the hydroelastic instability and asymmetric expansion of the inner and outer surfaces at the cellular level. 2 The layered anisotropic orientated cellulose fibrils induce hygroscopic movements of pine cones, 1 wheat awns, 3 orchid tree seedpods 6 and other plants. By mimicking the sophisticated hierarchical structures present in nature, the motion of polymer films has been successfully demonstrated in several cases. [23][24][25][26][27][28][29][30] For example, hydrogel bilayers embedded with intersecting inorganic platelets or cellulose fibrils have exhibited pine-cone-like bending and pod-like twisting motions. 24,31 However, the practical applications of these actuators were limited because of the low modulus and weak mechanical strength of the hydrogels. 32 Elastomer single layer films, such as azobenzene polymer films synthesized using an elaborate molecular design, 13,27 can achieve smart responsive curving. However, these films require a unidirectional stimulus to generate anisotropic contraction/expansion of their two sides; this factor limits the film thickness to the micrometer or sub-millimeter level. 27,[33][34][35] Therefore,

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“…On the other hand, the hygroscopic movements of pine cones 24 and ice plant seed capsules 22 , although slower, can function even when the host organisms are dead. Recently, enormous efforts have been paid to these bio-prototypes, with progress being made on responsive nanocomposites and surfaces 3 , energy generators and transducers 25,26 , programmable origami 27 , soft robotics [28][29][30] , smart gels [31][32][33] and artificial muscles [34][35][36] . Yet, most of the polymer actuators suffer from the relatively slow and small scale movements; furthermore, they are susceptible to severe circumstances and involve complex preparation such as multistep lithographic processes 21,37 .…”

mentioning

confidence: 99%

An instant multi-responsive porous polymer actuator driven by solvent molecule sorption

et al. 2014

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Fast actuation speed, large-shape deformation and robust responsiveness are critical to synthetic soft actuators. A simultaneous optimization of all these aspects without trade-offs remains unresolved. Here we describe porous polymer actuators that bend in response to acetone vapour (24 kPa, 20°C) at a speed of an order of magnitude faster than the state-ofthe-art, coupled with a large-scale locomotion. They are meanwhile multi-responsive towards a variety of organic vapours in both the dry and wet states, thus distinctive from the traditional gel actuation systems that become inactive when dried. The actuator is easy-tomake and survives even after hydrothermal processing (200°C, 24 h) and pressing-pressure (100 MPa) treatments. In addition, the beneficial responsiveness is transferable, being able to turn 'inert' objects into actuators through surface coating. This advanced actuator arises from the unique combination of porous morphology, gradient structure and the interaction between solvent molecules and actuator materials.

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Reversible patterning and actuation of hydrogels by electrically assisted ionoprinting

Cited by 414 publications

References 30 publications

Pneumatic Networks for Soft Robotics that Actuate Rapidly

Pneumatic Networks for Soft Robotics that Actuate Rapidly

A monolithic hydro/organo macro copolymer actuator synthesized via interfacial copolymerization

An instant multi-responsive porous polymer actuator driven by solvent molecule sorption

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