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Shi Z, Wang Z, Xiao K, Zhu B, Wang Y, Zhang X, Lin Z, Tan D, Xue L. Bioinspired Touch-Responsive Hydrogels for On-Demand Adhesion on Rough Surfaces. ACS APPLIED MATERIALS & INTERFACES 2024; 16:19819-19827. [PMID: 38564660 DOI: 10.1021/acsami.4c01914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Reversible adhesives are widely needed in our daily lives and industrial applications. However, robust and switchable adhesion on rough surfaces with on-demand attachment and detachment remains highly challenging. Here, we report a snail-mucus-inspired touch-responsive hydrogel (TRH), whose universal and robust adhesion is triggered by simple contact with the attaching surface. TRH is composed of a polymeric hydrogel and saturated sodium acetate (NaAc) and is prepared by one-pot synthesis. At room temperature, TRH remains in an amorphous and soft state, which allows it to conformally adapt to rough surfaces. The contact with the target surface triggers the crystallization of NaAc, which increases the modulus of TRH by an order of magnitude and interlocks with the target surfaces, achieving an adhesion of up to 204.84 ± 53.98 kPa. Upon heating, TRH returns to a soft state, facilitating easy detachment with adhesion of 5.12 ± 1.34 kPa. Meanwhile, the detached TRH is ready for the next adhesion without the need to be maintained at high temperature. TRH finds applications as a smart material for light-triggered adhesion switching, information encryption, and temperature sensors.
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Affiliation(s)
- Zhekun Shi
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
- Institute of Zhejiang University-Quzhou, Zhejiang Provincial Innovation Center of Advanced Chemicals Technology, Quzhou 324000, China
| | - Zhuo Wang
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
| | - Kangjian Xiao
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
| | - Bo Zhu
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
| | - Yan Wang
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
| | - Xiaolong Zhang
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
| | - Zhen Lin
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
| | - Di Tan
- School of Fashion and Textiles, The Hong Kong Polytechnic University, Hung Hom 999077, Hong Kong, China
| | - Longjian Xue
- School of Power and Mechanical Engineering, The Institute of Technological Science, Wuhan University, Wuhan 430072, China
- Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration (Wuhan University), Wuhan University, Wuhan 430072, China
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Zhu M, Ji S, Luo Y, Zhang F, Liu Z, Wang C, Lv Z, Jiang Y, Wang M, Cui Z, Li G, Jiang L, Liu Z, Chen X. A Mechanically Interlocking Strategy Based on Conductive Microbridges for Stretchable Electronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2101339. [PMID: 34978104 DOI: 10.1002/adma.202101339] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/21/2021] [Indexed: 06/14/2023]
Abstract
Stretchable electronics incorporating critical sensing, data transmission, display and powering functionalities, is crucial to emerging wearable healthcare applications. To date, methods to achieve stretchability of individual functional devices have been extensively investigated. However, integration strategies of these stretchable devices to achieve all-stretchable systems are still under exploration, in which the reliable stretchable interconnection is a key element. Here, solderless stretchable interconnections based on mechanically interlocking microbridges are developed to realize the assembly of individual stretchable devices onto soft patternable circuits toward multifunctional all-stretchable platforms. This stretchable interconnection can effectively bridge interlayer conductivity with tight adhesion through both conductive microbridges and selectively distributed adhesive polymer. Consequently, enhanced stretchability up to a strain of 35% (R/R0 ≤ 5) is shown, compared with conventional solder-assisted connections which lose electrical conduction at a strain of less than 5% (R/R0 ≈ 30). As a proof of concept, a self-powered all-stretchable data-acquisition platform is fabricated by surface mounting a stretchable strain sensor and a supercapacitor onto a soft circuit through solderless interconnections. This solderless interconnecting strategy for surface-mountable devices can be utilized as a valuable technology for the integration of stretchable devices to achieve all-soft multifunctional systems.
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Affiliation(s)
- Ming Zhu
- State Key Laboratory of Advanced Welding and Joining, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Shaobo Ji
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Yifei Luo
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Feilong Zhang
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zhihua Liu
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Changxian Wang
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zhisheng Lv
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Ying Jiang
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Ming Wang
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zequn Cui
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Guanglin Li
- Research Center for Neural Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Longtao Jiang
- State Key Laboratory of Advanced Welding and Joining, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
| | - Zhiyuan Liu
- Research Center for Neural Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Xiaodong Chen
- Innovative Center for Flexible Devices (iFLEX), Max Planck - NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Singapore
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Wang J, Wan Y, Wang X, Xia Z. Bioinspired Smart Materials With Externally-Stimulated Switchable Adhesion. FRONTIERS IN NANOTECHNOLOGY 2021. [DOI: 10.3389/fnano.2021.667287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Living organisms have evolved, over billions of years, to develop specialized biostructures with switchable adhesion for various purposes including climbing, perching, preying, sensing, and protecting. According to adhesion mechanisms, switchable adhesives can be divided into four categories: mechanically-based adhesion, liquid-mediated adhesion, physically-actuated adhesion and chemically-enhanced adhesion. Mimicking these biostructures could create smart materials with switchable adhesion, appealing for many engineering applications in robotics, sensors, advanced drug-delivery, protein separation, etc. Progress has been made in developing bioinspired materials with switchable adhesion modulated by external stimuli such as electrical signal, magnetic field, light, temperature, pH value, etc. This review will be focused on new advance in biomimetic design and synthesis of the materials and devices with switchable adhesion. The underlying mechanisms, design principles, and future directions are discussed for the development of high-performance smart surfaces with switchable adhesion.
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Mohammadi Nasab A, Luo A, Sharifi S, Turner KT, Shan W. Switchable Adhesion via Subsurface Pressure Modulation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:27717-27725. [PMID: 32449361 DOI: 10.1021/acsami.0c05367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Materials and devices with tunable dry adhesion have many applications, including transfer printing, climbing robots, and gripping in pick-and-place processes. In this paper, a novel soft device to achieve dynamically tunable dry adhesion via modulation of subsurface pneumatic pressure is introduced. Specifically, a cylindrical elastomer pillar with a mushroom-shaped cap and annular chamber that can be pressurized to tune the adhesion is investigated. Finite element-based mechanics models and experiments are used to design, understand, and demonstrate the adhesion of the device. Specifically, the device is designed using mechanics modeling such that the pressure applied inside the annular chamber significantly alters the stress distribution at the adhered interface and thus changes the effective adhesion strength. Devices made of polydimethylsiloxane (PDMS) with different elastic moduli were tested against glass, silicon, and aluminum substrates. Adhesion strengths (σ0) ranging from ∼37 kPa (between PDMS and glass) to ∼67 kPa (between PDMS and polished aluminum) are achieved for the nonpressurized state. For all cases, regardless of the material and roughness of the substrates, the adhesion strength dropped to 40% of the strength of the nonpressurized state (equivalent to a 2.5× adhesion switching ratio) by increasing the chamber pressure from 0.3σ0 to 0.6σ0. Furthermore, the strength drops to 20% of the unpressurized strength (equivalent to a 5× adhesion switching ratio) when the chamber pressure is increased to σ0.
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Affiliation(s)
- Amir Mohammadi Nasab
- Mechanical Engineering Department, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Aoyi Luo
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 220 South 33rd Street, Philadelphia, Pennsylvania 19104, United States
| | - Siavash Sharifi
- Mechanical Engineering Department, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Kevin T Turner
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 220 South 33rd Street, Philadelphia, Pennsylvania 19104, United States
| | - Wanliang Shan
- Mechanical Engineering Department, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, New York 13244, United States
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Jo W, Choi J, Kang HS, Kim M, Baik S, Lee BJ, Pang C, Kim HT. Programmable Fabrication of Submicrometer Bent Pillar Structures Enabled by a Photoreconfigurable Azopolymer. ACS APPLIED MATERIALS & INTERFACES 2020; 12:5058-5064. [PMID: 31809014 DOI: 10.1021/acsami.9b19420] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Anisotropic small structures found throughout living nature have unique functionalities as seen by Gecko lizards. Here, we present a simple yet programmable method for fabricating anisotropic, submicrometer-sized bent pillar structures using photoreconfiguration of an azopolymer. A slant irradiation of a p-polarized light on the pillar structure of an azopolymer simply results in a bent pillar structure. By combining the field-gradient effect and directionality of photofluidization, control of the bending shape and the curvature is achieved. With the bent pillar patterned surface, anisotropic wetting and directional adhesion are demonstrated. Moreover, the bent pillar structures can be transferred to other polymers, highlighting the practical importance of this method. We believe that this pragmatic method to fabricate bent pillars can be used in a reliable manner for many applications requiring the systematic variation of a bent pillar structure.
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Affiliation(s)
| | | | - Hong Suk Kang
- Interface Materials and Chemical Engineering Research Center , Korea Research Institute of Chemical Technology (KRICT) , Daejeon 34114 , Republic of Korea
| | | | - Sangyul Baik
- SKKU Advanced Institute of Nanotechnology (SAINT) , Sungkyunkwan University , Suwon , Kyunggi-do 16419 , Republic of Korea
| | | | - Changhyun Pang
- SKKU Advanced Institute of Nanotechnology (SAINT) , Sungkyunkwan University , Suwon , Kyunggi-do 16419 , Republic of Korea
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Novel Janus Fibrous Membranes with Enhanced Directional Water Vapor Transmission. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9163302] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Novel hydrophobic/hydrophilic Janus fibrous membranes, the poly[4,4′-methylenebis (phenylisocyanate)-alt-1,4-butanediol/di(propylene glycol)/plycaprolactone] (PU) fibrous membrane as the hydrophobic layer and cellulose acetate (CA) fibrous membrane as the hydrophilic layer, were fabricated by the so-called “layer-by-layer” electrospinning technology. A series of the PU/CA Janus membranes with different electrospinning time of the CA layers by which the thickness of hydrophilic layer can be controlled were also prepared to uncover its influence on the directional water vapor transmission. The results showed that water vapor transmission capability from the hydrophobic side to the hydrophilic side of the PU/CA Janus fibrous membrane was enhanced rather than that from the reverse direction of the same membrane. The optimal water vapor transmission capacity existed when the electrospinning time of CA fibrous membrane reached 15 min. Such enhanced water vapor transmission originated because of the asymmetric wettability of the Janus membrane and the strong force to draw tiny water droplet from the hydrophobic side to the hydrophilic side. The novel understanding is useful for facile designing and fabrication of efficient moisture permeable fabrics and clothing.
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7
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In Situ Atomic Force Microscopy Studies on Nucleation and Self-Assembly of Biogenic and Bio-Inspired Materials. MINERALS 2017. [DOI: 10.3390/min7090158] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Kim SM, Kim J, Kang SM, Jang S, Kang D, Moon SE, Kim HN, Yoon H. Directional Clustering of Slanted Nanopillars by Elastocapillarity. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:3764-3769. [PMID: 27273859 DOI: 10.1002/smll.201600730] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/07/2016] [Indexed: 06/06/2023]
Abstract
The unidirectional clustering induced by capillary force of drying liquids between pillars is investigated and a theoretical model to set a criterion of the unidirectional clustering of the slanted nanopillars is proposed.
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Affiliation(s)
- Sang Moon Kim
- Department of Mechanical Engineering, Incheon National University, Incheon, 406-772, South Korea
- Global Frontier Center for Multiscale Energy System, Seoul National University, Seoul, 151-744, South Korea
| | - Junsoo Kim
- 3D New Devices Research Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700, South Korea
| | - Seong Min Kang
- Global Frontier Center for Multiscale Energy System, Seoul National University, Seoul, 151-744, South Korea
- Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-742, South Korea
| | - Segeun Jang
- Global Frontier Center for Multiscale Energy System, Seoul National University, Seoul, 151-744, South Korea
- Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-742, South Korea
| | - Daeshik Kang
- Global Frontier Center for Multiscale Energy System, Seoul National University, Seoul, 151-744, South Korea
- Department of Mechanical Engineering, Ajou University, Suwon, 443-749, South Korea
| | - Seung Eon Moon
- 3D New Devices Research Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700, South Korea
| | - Hong Nam Kim
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology, Seoul, 136-791, South Korea
| | - Hyunsik Yoon
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science & Technology, Seoul, 139-743, South Korea
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9
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Lin H, Qu Z, Meredith JC. Pressure sensitive microparticle adhesion through biomimicry of the pollen-stigma interaction. SOFT MATTER 2016; 12:2965-2975. [PMID: 26883733 DOI: 10.1039/c5sm02845k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Many soft biomimetic synthetic adhesives, optimized to support macroscopic masses (∼kg), have been inspired by geckos, insects and other animals. Far less work has investigated bioinspired adhesion that is tuned to micro- and nano-scale sizes and forces. However, such adhesive forces are extremely important in the adhesion of micro- and nanoparticles to surfaces, relevant to a wide range of industrial and biological systems. Pollens, whose adhesion is critical to plant reproduction, are an evolutionary-optimized system for biomimicry to engineer tunable adhesion between particles and micro-patterned soft matter surfaces. In addition, the adhesion of pollen particles is relevant to topics as varied as pollinator ecology, transport of allergens, and atmospheric phenomena. We report the first observation of structurally-derived pressure-sensitive adhesion of a microparticle by using the sunflower pollen and stigma surfaces as a model. This strong, pressure-sensitive adhesion results from interlocking between the pollen's conical spines and the stigma's receptive papillae. Inspired by this behavior, we fabricated synthetic polymeric patterned surfaces that mimic the stigma surface's receptivity to pollen. These soft mimics allow the magnitude of the pressure-sensitive response to be tuned by adjusting the size and spacing of surface features. These results provide an important new insight for soft material adhesion based on bio-inspired principles, namely that ornamented microparticles and micro-patterned surfaces can be designed with complementarity that enable a tunable, pressure-sensitive adhesion on the microparticle size and length scale.
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Affiliation(s)
- Haisheng Lin
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, USA.
| | - Zihao Qu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, USA.
| | - J Carson Meredith
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, USA.
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10
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Kang SM, Yoon H. One step fabrication of polymeric ratchet structures of diverse tilting angles. RSC Adv 2016. [DOI: 10.1039/c6ra06099d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A novel method to fabricate asymmetric ratchet-like micro structures with various tilting angles is presented by controlling the light transmission pathway with double-layered Lucius prism arrays.
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Affiliation(s)
- Seong Min Kang
- Global Frontier Center for Multiscale Energy System
- Seoul National University
- Seoul 151-744
- Korea
- Department of Mechanical and Aerospace Engineering
| | - Hyunsik Yoon
- Department of Chemical and Biomolecular Engineering
- Seoul National University of Science & Technology
- Seoul
- Korea
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Filippov AE, Popov VL, Gorb SN. The functional significance of density and distribution of outgrowths on co-opted contact pairs in biological arresting systems. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140032. [PMID: 25533090 DOI: 10.1098/rstb.2014.0032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Microstructures responsible for temporary arresting of contacting surfaces are widely distributed on surfaces in different organisms. Recent morphological studies show that these structures have different density of outgrowths and not ideal distribution pattern on both complementary parts of the contact. One can suggest that this difference is optimized by natural selection to get stronger mechanical arrest within the system. In this paper, we simulate such a system numerically, both in the frames of continuous contact and discrete dynamical models to prove this hypothesis and elucidate other aspects of optimization of such mechanical adhesive systems.
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Affiliation(s)
- Alexander E Filippov
- Department of Functional Morphology and Biomechanics, Zoological Institute of the University of Kiel, Am Botanischen Garten 1-9, 24098 Kiel, Germany Donetsk Institute for Physics and Engineering, National Academy of Sciences, 83114 Donetsk, Ukraine
| | - Valentin L Popov
- FG Systemdynamik und Reibungsphysik, Technische Universität Berlin, Institut für Mechanik, Sekr. C8-4, Raum M 122, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute of the University of Kiel, Am Botanischen Garten 1-9, 24098 Kiel, Germany
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Wang Z, Gu P, Wu X. Gecko-inspired bidirectional double-sided adhesives. SOFT MATTER 2014; 10:3301-3310. [PMID: 24637918 DOI: 10.1039/c3sm52921e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A new concept of gecko-inspired double-sided adhesives (DSAs) is presented. The DSAs, constructed by dual-angled (i.e. angled base and angled tip) micro-pillars on both sides of the backplane substrate, are fabricated by combinations of angled etching, mould replication, tip modification, and curing bonding. Two types of DSA, symmetric and antisymmetric (i.e. pillars are patterned symmetrically or antisymmetrically relative to the backplane), are fabricated and studied in comparison with the single-sided adhesive (SSA) counterparts through both non-conformal and conformal tests. Results indicate that the DSAs show controllable and bidirectional adhesion. Combination of the two pillar-layers can either amplify (for the antisymmetric DSA, providing a remarkable and durable adhesion capacity of 25.8 ± 2.8 N cm⁻² and a high anisotropy ratio of ∼8) or counteract (for the symmetric DSA, generating almost isotropic adhesion) the adhesion capacity and anisotropic level of one SSA (capacity of 16.2 ± 1.7 N cm⁻² and anisotropy ratio of ∼6). We demonstrate that these two DSAs can be utilized as a facile fastener for two individual objects and a small-scale delivery setup, respectively, complementing the functionality of the commonly studied SSA. As such, the double-sided patterning is believed to be a new branch in the further development of biomimetic dry adhesives.
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Affiliation(s)
- Zhengzhi Wang
- Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China.
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Abstract
The microstructures on elytral surface of aquatic beetles belonging to Hydrophilidae and Dytiscidae were observed under an environment scanning microscope, and the wettabilities were determined with an optical contact angle meter. The results show the elytral surfaces are relatively smooth compared to the structures of other insects such as the butterfly wing scales or cicada wing protrusions. They exhibit a polygonal structuring with grooves and pores being the main constituent units. The contact angles (CAs) range from 47.1oto 82.1o. The advancing and receding angles were measured by injecting into and withdrawing a small amount of water on the most hydrophilic (with a contact angle of 47.1o) and hydrophobic (with a contact angle of 82.1o) elytral surfaces, which illustrates the vital role of three-phase contact line (TCL) in the wetting mechanism of aquatic beetle elytral surfaces.
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Rahmawan Y, Kang SM, Lee SY, Suh KY, Yang S. Enhanced Shear Adhesion by Mechanical Interlocking of Dual-Scaled Elastomeric Micropillars With Embedded Silica Particles. MACROMOL REACT ENG 2013. [DOI: 10.1002/mren.201300149] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yudi Rahmawan
- Department of Materials Science and Engineering; University of Pennsylvania; 3231 Walnut Street Philadelphia Pennsylvania 19104 USA
| | - Seong Min Kang
- Department of Mechanical and Aerospace Engineering; Seoul National University; 1 Gwanak-ro, Gwanak-gu Seoul 151-742 Korea
| | - Su Yeon Lee
- Department of Materials Science and Engineering; University of Pennsylvania; 3231 Walnut Street Philadelphia Pennsylvania 19104 USA
| | - Kahp-Yang Suh
- Department of Mechanical and Aerospace Engineering; Seoul National University; 1 Gwanak-ro, Gwanak-gu Seoul 151-742 Korea
| | - Shu Yang
- Department of Materials Science and Engineering; University of Pennsylvania; 3231 Walnut Street Philadelphia Pennsylvania 19104 USA
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