Scalable and continuous fabrication of bio-inspired dry adhesives with a thermosetting polymer

Soft Matter ◽  
2018 ◽  
Vol 14 (14) ◽  
pp. 2586-2593 ◽  
Author(s):  
Sung Ho Lee ◽  
Sung Woo Kim ◽  
Bong Su Kang ◽  
Pahn-Shick Chang ◽  
Moon Kyu Kwak
Keyword(s):  
Fabrication Method ◽  
Dry Adhesive ◽  
Nano Structure ◽  
Dry Adhesives ◽  
Thermosetting Polymer ◽  
Continuous Fabrication

Continuous fabrication method of micro/nano structure using thermosetting polymer and dry adhesive production as its application are presented.

scholarly journals Continuous Fabrication of Wide-Tip Microstructures for Bio-Inspired Dry Adhesives via Tip Inking Process

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Sung Ho Lee ◽  
Cheol Woo Park ◽  
Moon Kyu Kwak
Keyword(s):  
Continuous Process ◽  
Reversed Phase ◽  
Fabrication Process ◽  
New Method ◽  
Dry Adhesive ◽  
Microstructure Fabrication ◽  
High Durability ◽  
Dry Adhesives ◽  
Process System ◽  
Continuous Fabrication

In this paper, we report a new method for continuous fabrication of dry adhesives composed of microstructures with mushroom-shaped ends. Conventional mushroom microstructure fabrication is performed with a simple molding technique using a reversed phase master. In a typical fabrication process, thin- and wide-tip portions may be ripped during demolding, making it difficult to use in a continuous process. It is also difficult to apply the mushroom structure master to a continuous process system in roll form. Here, a continuous fabrication process was developed by applying the method of fabricating a wide tip using a tip inking method after forming a micropillar. Through the continuous process, the dry adhesive was successfully fabricated and the durability was measured with a reasonable pull-off strength (13 N/cm2). In addition to the reasonable adhesion, high durability is guaranteed, and fabricated dry adhesives are expected to be used in various fields.

Highly flexible and self-adaptive dry adhesive end-effectors for precision robotics

Soft Matter ◽  
2019 ◽  
Vol 15 (29) ◽  
pp. 5827-5834 ◽  
Author(s):  
Sung Ho Lee ◽  
Insol Hwang ◽  
Bong Su Kang ◽  
Hoon Eui Jeong ◽  
Moon Kyu Kwak
Keyword(s):  
Structural Design ◽  
Dry Adhesive ◽  
Dry Adhesives ◽  
Adhesion Performance ◽  
End Effectors ◽  
Self Adaptive

For wide application of dry adhesives, we have realized the improvement of adhesion performance on inclined target substrate through structural design in macroscale. The improved dry adhesives exhibit stable properties in inclined targets.

Continuous fabrication of scalable 2-dimensional (2D) micro- and nanostructures by sequential 1D mechanical patterning processes

Nanoscale ◽  
2014 ◽  
Vol 6 (24) ◽  
pp. 14636-14642 ◽  
Author(s):  
Jong G. Ok ◽  
Ashwin Panday ◽  
Taehwa Lee ◽  
L. Jay Guo
Keyword(s):  
Nano Structure ◽  
Continuous Fabrication

We present a versatile and simple methodology for continuous and scalable 2D micro/nano-structure fabrication through sequential 1D patterning strokes.

High Aspect Ratio Polymer Micro/Nano-Structure Manufacturing Using Nanoembossing, Nanomolding and Directed Self-Assembly

2003 ◽  
Author(s):  
Metin Sitti
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly ◽  
Scanning Tunneling ◽  
Nano Structure ◽  
Liquid Polymer ◽  
Dry Adhesives ◽  
Liquid Polymers ◽  
Assembly Technique ◽  
Dc Electric Field

This paper proposes three methods to fabricate synthetic gecko foot-hair high aspect ratio polymer micro/nanostructures. In the first method, nano-robotically indented templates are molded with liquid polymers, and the cured polymer is peeled off or etched away. Atomic force microscope and scanning tunneling microscope probe tips are used to emboss/indent flat wax surfaces, and silicone rubber micro/nano-bump structures are demonstrated. The second one uses a self-organized polycarbonate nano-pore membrane as the molding template. PDMS is molded into these micro/nano-pores under vacuum, and 1:2 and 1:9 aspect ratio pillar structures with 5 micron and 0.6 micron diameters are manufactured successfully. Finally, a directed self-assembly technique is proposed to grow regularly spaced and oriented micro/nano-pillars. Here, instability of a liquid polymer thinfilm under a DC electric field is used to grow nano-pillars, and stretching and shearing of the grown hairs enable high aspect ratio and oriented hair structures. These hair structures will be utilized as novel biomimetic dry adhesives in future miniature space and surgical robot feet.

scholarly journals Continuous Tip Widening Technique for Roll-to-Roll Fabrication of Dry Adhesives

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 349 ◽  
Author(s):  
Sung Lee ◽  
Hoon Yi ◽  
Cheol Park ◽  
Hoon Jeong ◽  
Moonkyu Kwak
Keyword(s):  
Production Technology ◽  
Adhesion Force ◽  
Continuous Production ◽  
Productivity Improvement ◽  
Dry Adhesive ◽  
Polyurethane Acrylate ◽  
Roll To Roll ◽  
Dry Adhesives ◽  
Pillar Structure ◽  
Capillary Force Lithography

In this study, we reported continuous partial curing and tip-shaped modification methods for continuous production of dry adhesive with microscale mushroom-shaped structures. Typical fabrication methods of dry adhesive with mushroom-shaped structures are less productive due to the failure of large tips on pillar during demolding. To solve this problem, a typical pillar structure was fabricated through partial curing, and tip widening was realized through applying the proper pressure. Polyurethane acrylate was used in making the mushroom structure using two-step UV-assisted capillary force lithography (CFL). To make the mushroom structure, partial curing was performed on the micropillar, followed by tip widening. Dry adhesives with properties similar to those of typical mushroom-shaped dry adhesives were fabricated with reasonable adhesion force using the two-step UV-assisted CFL. This production technology was applied to the roll-to-roll process to improve productivity, thereby realizing continuous production without any defects. Such a technology is expected to be applied to various fields by achieving the productivity improvement of dry adhesives, which is essential for various applications.

scholarly journals Improving controllable adhesion on both rough and smooth surfaces with a hybrid electrostatic/gecko-like adhesive

2014 ◽  
Vol 11 (93) ◽  
pp. 20131089 ◽  
Author(s):  
Donald Ruffatto ◽  
Aaron Parness ◽  
Matthew Spenko
Keyword(s):  
Relative Effectiveness ◽  
Adhesive Force ◽  
Similar Process ◽  
Ceramic Tiles ◽  
Surface Type ◽  
Dry Adhesive ◽  
Feedback Cycle ◽  
Dry Adhesion ◽  
Dry Adhesives ◽  
Electrostatic Adhesion

This paper describes a novel, controllable adhesive that combines the benefits of electrostatic adhesives with gecko-like directional dry adhesives. When working in combination, the two technologies create a positive feedback cycle whose adhesion, depending on the surface type, is often greater than the sum of its parts. The directional dry adhesive brings the electrostatic adhesive closer to the surface, increasing its effect. Similarly, the electrostatic adhesion helps engage more of the directional dry adhesive fibrillar structures, particularly on rough surfaces. This paper presents the new hybrid adhesive's manufacturing process and compares its performance to three other adhesive technologies manufactured using a similar process: reinforced PDMS, electrostatic and directional dry adhesion. Tests were performed on a set of ceramic tiles with varying roughness to quantify its effect on shear adhesive force. The relative effectiveness of the hybrid adhesive increases as the surface roughness is increased. Experimental data are also presented for different substrate materials to demonstrate the enhanced performance achieved with the hybrid adhesive. Results show that the hybrid adhesive provides up to 5.1× greater adhesion than the electrostatic adhesive or directional dry adhesive technologies alone.

scholarly journals Durable Soft Mold for Imprinting of High-Adhesive Resin

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 137
Author(s):  
Jihoon Lee ◽  
Sung Ho Lee ◽  
Moon Kyu Kwak
Keyword(s):  
Operation Time ◽  
Surface Characteristics ◽  
Imprint Lithography ◽  
Nano Structure ◽  
Uv Curable ◽  
High Adhesion ◽  
Optical Adhesive ◽  
Soft Mold ◽  
Increasing Demand ◽  
Continuous Fabrication

A variety of polymer resins have been used to fabricate micro/nano structures via imprint lithography. In addition, with an interest in productivity, there is an increasing demand for the study of the process of easily demolding a cured resin from a mold for continuous fabrication of micro/nanostructures applying imprint lithography to the roll-type equipment. Among these polymer resins, Norland optical adhesive (NOA) in particular is widely used to fabricate micro/nano structure-based functional surfaces because of its shape memory characteristics, biocompatibility, and great optical characteristics. However, the cured NOA is originally used as an epoxy-based adhesive with its high adhesion. NOA has many advantages as a UV-curable adhesive, but as a resin in the imprint process, such adhesion brings a limitation. This high adhesion of cured NOA causes defects in the mold during the demolding process, so it is difficult to apply it to the continuous fabrication process. Here, we present a durable polyurethane acrylate (PUA) soft mold capable of clean demolding of an epoxy-based polymer resin having high adhesion by depositing metal on a surface. Au and Ni were deposited to a thickness of 100 Å by using an E-beam evaporator. To verify the surface characteristics, each metal-deposited soft mold was compared with the previously used soft mold by measuring the contact angle and calculating surface energy. To test a performance of our soft mold, we imprinted nanoline pattern with NOA as a resin using metal-deposited soft mold in roll to roll (R2R) process for more than 240 replications for 90 min of operation time. It is expected that this study can be used for mass production of pattern with epoxy-based patterns required in many fields.

Design of Track-Based Climbing Robots Using Dry Adhesives

2017 ◽  
Author(s):  
Matthew W. Powelson ◽  
Stephen L. Canfield
Keyword(s):  
Contact Surface ◽  
Climbing Robot ◽  
Complete Model ◽  
Climbing Robots ◽  
Dry Adhesive ◽  
Full Contact ◽  
Robot Systems ◽  
Dry Adhesives ◽  
Adhesion Model ◽  
Track Surface

This paper focuses on the design of track-type climbing robots using dry adhesives to generate tractive forces between the robot and climbing surface to maintain equilibrium while in motion. When considering the design of these climbing robots, there are two primary elements of focus: the adhesive mechanisms at the track-surface interface and the distribution of these forces over the full contact surface (the tracks). This paper will present an approach to integrate a generic adhesion model and a track suspension system into a complete model that can be used to design general climbing robot systems utilizing a broad range of dry adhesive technologies.

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