Bioinspired photocontrollable microstructured transport device

Kizilkan, Emre; Strueben, Jan; Staubitz, Anne; Gorb, Stanislav N.

doi:10.1126/scirobotics.aak9454

Cited by 122 publications

(102 citation statements)

References 29 publications

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“…b) Electrostatics can be developed to create i) rigid, ii) flexible, or iii,iv) soft electroadhesive materials. [166] Copyright 2017, American Association for the Advancement of Science. [163] Copyright 2014, Royal Society.…”

Section: Fluidic Switchingmentioning

confidence: 99%

“…[177][178][179] These approaches can be applied to the adhesion of solids as demonstrated with azobenzene-containing materials liquid crystal elastomers (LCEs), [180,181] where a backing substrate changes shape under the application of UV light, causing adhesion to decrease by a factor of 2.7. [166] Photoactive adhesives can also be generated with photoinduced cros slinking. [58,59,182] Supramolecular polymers can be used which bond and debond under the application of UV light.…”

Section: Lightmentioning

confidence: 99%

Section: Fluidic Switchingmentioning

confidence: 99%

See 2 more Smart Citations

Switchable Adhesives for Multifunctional Interfaces

Croll

Hosseini

Bartlett

2019

Adv Materials Technologies

109

106

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The reliable bonding or attachment of materials is critical in many industries, is a common necessity of daily life, and is key to functionality in numerous biological settings. [1][2][3][4][5][6][7][8][9][10][11] Adhesives Joining two materials with an adhesive is an extremely common activity, but is most often irreversible. However, emerging and current applications ranging from consumer and medical products to soft robotics and wearable bio-monitoring devices demand strong adhesives which can be easily removed on-demand and subsequently reused. This requires new paradigms in adhesive science and engineering, resulting in the emergence of new classes of multifunctional switchable adhesives. Here summarized is the current state of the art in switchable adhesive systems, focusing on how devices fit into the basic science of adhesion while providing performance metrics for comparison across current approaches. Using fracture mechanics as a guide, systems are classified as functioning under one of three basic mechanisms: near-interface, contact area, or mechanical. These mechanisms must be initiated or "triggered" by a specific input, which can include mechanical, electromagnetic, fluidic, or thermal stimuli. Triggers and adhesion switching performance are compared through the use of a "switching ratio," the interfacial energy release rate, and an estimate of mechanism timing. Finally, it is discussed that how the fundamental mechanisms relate to challenges and opportunities for switchable interfaces in future applications and adhesive systems.

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Section: Fluidic Switchingmentioning

confidence: 99%

Section: Lightmentioning

confidence: 99%

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Switchable Adhesives for Multifunctional Interfaces

Croll

Hosseini

Bartlett

2019

Adv Materials Technologies

109

106

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“…This unique adhesive capability of geckos has led to the development of advanced adhesives, including dry adhesives, which unlike chemical adhesives, leave no residue [3]. Such dry adhesives generally have micro-nano array structures, and are expected to be suitable for robotic end-effectors [4][5][6][7]. At present, there are generally two main types of materials being researched as materials for gecko-inspired dry adhesives [8]: Synthetic polymers [5,9,10] and vertically-aligned carbon nanotubes (VACNTs) [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydrogen Concentration on the Growth of Carbon Nanotube Arrays for Gecko-Inspired Adhesive Applications

Duan

et al. 2017

Coatings

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Vertically-aligned carbon nanotubes (VACNTs) have extraordinary structural and mechanical properties, and have been considered as potential candidates for creating dry adhesives inspired by adhesive structures in nature. Catalytic chemical vapor deposition is widely used to grow VACNTs; however, the influential mechanism of VACNT preparation parameters (such as H 2 concentration) on its adhesion property is not clear, making accurate control over the structure of VACNTs adhesive an ongoing challenge. In this article, we use electron beam-deposited SiO 2 /Al 2 O 3 as a support layer, Fe as catalyst, and C 2 H 4 /H 2 gas mixtures as a feed gas to prepare VACNTs, while varying the ratio of the reducing atmosphere (H 2 ) from 0% to 35%. VACNTs synthesized at a 15% H 2 concentration (5 mm × 5 mm in size) can support a maximal weight of 856 g, which indicates a macroscopic shear adhesive strength of 34 N/cm 2 . We propose a hydrogen-concentration-dependent model for the shear adhesive performance of VACNTs. By adjusting the amount of hydrogen present during the reaction, the morphology and quality of the prepared VACNTs can be precisely controlled, which significantly influences its shear adhesive performance. These results are advantageous for the application of carbon nanotubes as dry adhesives.

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Section: Polymeric Photoactuators: Moving Toward Artificial Musclesmentioning

confidence: 99%

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

Chang

Fedele

Priimägi

et al. 2019

Advanced Optical Materials

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systems interact with artificial materials, researchers have now assembled a versatile toolkit of materials and processes that allows one to fine-tune interactions at the interface, tailoring specific biological responses on demand. These strategies for biocontrol can be broadly categorized as chemical (charge, ligand presence, surface groups), material changes (moisture content, stiffness), or morphological changes (molecular orientation, surface topography, or mechanical actuation). Rational design of materials for biological interface applications has a unique set of challenges due to the unique requirements of a wide range of biological systems, since different tissues present specific compositions, with their own elasticity, structural organization, and triggering mechanisms. Even within a single organ or tissue, mechanical properties can vary widely depending on the region. A recent study of viscoelasticity in live mouse brain tissue for example found a tenfold difference within the brain depending on the region and morphological structure studied. [2] However, most biological tissues are far less stiff, and far more viscoelastic than typical artificial materials employed at their interface, especially early artificial cell culture materials, which can be much stiffer than in vivo extracellular matrix by many orders of magnitude. [3] In vivo, cells interface with a surrounding microenvironment consisting of an intricate macromolecular network of proteins and sugars swollen in an aqueous media gel. Therefore, the interaction between cells and the extracellular matrix (ECM) in the body is complex and involves a variety of cues related to topography, chemical markers, protein composition, solubility factors, and mechanical properties such as stiffness and elasticity (Figure 1a). [4] Yet much research over the past decades was focused on studying in vitro the effects of each of these signals on cell behavior, with a particular interest on the chemical factors, whereas only recently more advanced biomaterials with controlled physicomechanical properties have been developed, such as those with tunable and variable stiffness, alignment and orientation of key functional groups, and mechanical actuation. There is a large range of stiffness in human tissue, where bone (≈100 GPa) is nine orders of magnitude harder than brain tissue (≈0.1 kPa). [4] Therefore, biomaterial researchers assume a complex task of providing materials and processing technologies for controlling stiffness and micro-and nanostructures in Photoreversible optically switchable azo dye molecules in polymer-based materials can be harnessed to control a wide range of physical, chemical, and mechanical material properties in response to light, that can be exploited for optical control over the bio-interface. As a stimulus for reversibly influencing adjacent biological cells or tissue, light is an ideal triggering mechanism, since it can be highly localized (in time and space) for precise and dynamic control over a biosystem, and low-power visible light...

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Bioinspired photocontrollable microstructured transport device

Abstract: A transportation device can be tunably controlled by the ultraviolet actuation of a liquid crystal elastomer.

Cited by 122 publications

References 29 publications

Switchable Adhesives for Multifunctional Interfaces

Switchable Adhesives for Multifunctional Interfaces

Effect of Hydrogen Concentration on the Growth of Carbon Nanotube Arrays for Gecko-Inspired Adhesive Applications

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

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