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Wang Q, Xie H, Liu J, Liu C. Heterogeneous nucleation of argon vapor on the nanostructure surface with molecular dynamics simulation. J Mol Graph Model 2020; 100:107674. [PMID: 32750651 DOI: 10.1016/j.jmgm.2020.107674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 11/21/2022]
Abstract
The study of vapor condensation on surface has important engineering significance. The condensation nucleation process of vapor on substrates with different pillar structures is studied through molecular dynamic simulation. The condensation droplets on the pillar with various heights and solid fractions exhibit Wenzel state, Cassie state and the transformation from Wenzel state to Cassie state. The results show that the condensation efficiencies are correlated with the state of droplet and it is explained from the perspective of heat transfer. For the Wenzel state, the droplet fills the gap of pillar and the form of the heat conduction change with the growth of cluster. In the initial of condensation droplets, the heat conduction is similar with various heights of pillar. As the condensation droplets grow, the efficiency of heat conduction enhances with the increasing of height of pillar. For the Cassie state, the form of heat conduction is perpetual during the condensation process with the thermal resistance of the droplet dominated due to the droplets suspended on the pillar. The efficiency of heat transfer is insensitive to the height of pillar. The form of heat conduction for the transformation state transforms from Wenzel state to Cassie state leading to the reduction of condensation rate. The droplet formed in the Wenzel state has the higher transfer efficiency than the Cassie one.
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Lee WK, Jung WB, Rhee D, Hu J, Lee YAL, Jacobson C, Jung HT, Odom TW. Monolithic Polymer Nanoridges with Programmable Wetting Transitions. Adv Mater 2018; 30:e1706657. [PMID: 29952092 DOI: 10.1002/adma.201706657] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 04/15/2018] [Indexed: 06/08/2023]
Abstract
This paper describes polymeric nanostructures with dynamically tunable wetting properties. Centimeter-scale areas of monolithic nanoridges can be generated by strain relief of thermoplastic polyolefin films with fluoropolymer skin layers. Changing the amount of strain results in polyolefin ridges with aspect ratios greater than four with controlled feature densities. Surface chemistry and topography are demonstrated to be able to be tailored by SF6 -plasma etching to access multiple wetting states: Wenzel, Cassie-Baxter, and Cassie-impregnating states. Reversible transitions among the wetting states can be realized in a programmable manner by cyclic stretching and reshrinking the patterned substrates without delamination and cracking.
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Affiliation(s)
- Won-Kyu Lee
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Woo-Bin Jung
- Department of Chemical and Biomolecular Engineering (BK-21 Plus), Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yusong-gu, Daejeon, 34141, Republic of Korea
| | - Dongjoon Rhee
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Jingtian Hu
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Young-Ah Lucy Lee
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Christian Jacobson
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Hee-Tae Jung
- Department of Chemical and Biomolecular Engineering (BK-21 Plus), Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yusong-gu, Daejeon, 34141, Republic of Korea
| | - Teri W Odom
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
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Abstract
Enhancing the mobility of liquid droplets on rough surfaces is of great interest in industry, with applications ranging from condensation heat transfer to water harvesting to the prevention of icing and frosting. The mobility of a liquid droplet on a rough solid surface has long been associated with its wetting state. When liquid drops are sitting on the top of the solid textures and air is trapped underneath, they are in the Cassie state. When the drops impregnate the solid textures, they are in the Wenzel state. While the Cassie state has long been associated with high droplet mobility and the Wenzel state with droplet pinning, our work challenges this existing convention by showing that both Cassie and Wenzel state droplets can be highly mobile on nanotexture-enabled slippery rough surfaces. Our surfaces were developed by engineering hierachical nano- and microscale textures and infusing liquid lubricant into the nanotextures alone to create a highly slippery rough surface. We have shown that droplet mobility can be maintained even after the Cassie-to-Wenzel transition. Moreover, the discovery of the slippery Wenzel state allows us to assess the fundamental limits of the classical and recent Wenzel models at the highest experimental precision to date, which could not be achieved by any other conventional rough surface. Our results show that the classical Wenzel eq (1936) cannot predict the wetting behaviors of highly wetting liquids in the Wenzel state.
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Affiliation(s)
- Xianming Dai
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Birgitt Boschitsch Stogin
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Shikuan Yang
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Tak-Sing Wong
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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Butt HJ, Vollmer D, Papadopoulos P. Super liquid-repellent layers: The smaller the better. Adv Colloid Interface Sci 2015; 222:104-9. [PMID: 24996450 DOI: 10.1016/j.cis.2014.06.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 06/03/2014] [Accepted: 06/03/2014] [Indexed: 11/29/2022]
Abstract
Super liquid-repellent layers need to have a high impalement pressure and high contact angles, in particular a high apparent receding contact angle. Here, we demonstrate that to achieve both, the features constituting the layer should be as small as possible. Therefore, two models for super liquid-repellent layers are theoretically analyzed: A superhydrophobic layer consisting of an array of cylindrical micropillars and a superamphiphobic layer of an array of pillars of spheres. For the cylindrical micropillars a simple expression for the apparent receding contact angle is derived. It is based on a force balance rather than a thermodynamic approach. The model is supported by confocal microscope images of a water drop on an array of hydrophobic cylindrical pillars. The ratio of the width of a pillar w to the center-to-center spacing a is a primary factor in controlling the receding angle. Keeping the ratio w/a constant, the absolute size of surface features should be as small as possible, to maximize the impalement pressure.
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Affiliation(s)
- Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
| | - Doris Vollmer
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
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Ciasca G, Papi M, Palmieri V, Chiarpotto M, Di Claudio S, De Ninno A, Giovine E, Campi G, Gerardino A, Businaro L, De Spirito M. Controlling DNA Bundle Size and Spatial Arrangement in Self-assembled Arrays on Superhydrophobic Surface. Nanomicro Lett 2014; 7:146-151. [PMID: 30464965 PMCID: PMC6223938 DOI: 10.1007/s40820-014-0027-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/28/2014] [Indexed: 06/05/2023]
Abstract
The use of superhydrophobic surfaces (SHSs) is now emerging as an attractive platform for the realization of one-dimensional (1D) nanostructures with potential applications in many nanotechnological and biotechnological fields. To this purpose, a strict control of the nanostructures size and their spatial arrangement is highly required. However, these parameters may be strongly dependent on the complex evaporation dynamics of the sessile droplet on the SHS. In this work, we investigated the effect of the evaporation dynamics on the size and the spatial arrangement of self-assembled 1D DNA bundles. Our results reveal that different arrangements and bundle size distributions may occur depending on droplet evaporation stage. These results contribute to elucidate the formation mechanism of 1D nanostructures on SHSs.
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Affiliation(s)
- Gabriele Ciasca
- Istituto di Fisica, Universitá Cattolica SC, L.go Francesco Vito 1, 00168 Rome, Italy
| | - Massimiliano Papi
- Istituto di Fisica, Universitá Cattolica SC, L.go Francesco Vito 1, 00168 Rome, Italy
| | - Valentina Palmieri
- Istituto di Fisica, Universitá Cattolica SC, L.go Francesco Vito 1, 00168 Rome, Italy
| | - Michela Chiarpotto
- Istituto di Fisica, Universitá Cattolica SC, L.go Francesco Vito 1, 00168 Rome, Italy
| | - Simone Di Claudio
- Istituto di Fisica, Universitá Cattolica SC, L.go Francesco Vito 1, 00168 Rome, Italy
| | - Adele De Ninno
- Istituto di Fotonica e Nanotecnologie-CNR, Via Cineto Romano 42, 00156 Rome, Italy
| | - Ennio Giovine
- Istituto di Fotonica e Nanotecnologie-CNR, Via Cineto Romano 42, 00156 Rome, Italy
| | - Gaetano Campi
- Institute of Crystallography-CNR, Via Salaria Km 29, 0016 Monterotondo, Rome Italy
| | - Annamaria Gerardino
- Istituto di Fotonica e Nanotecnologie-CNR, Via Cineto Romano 42, 00156 Rome, Italy
| | - Luca Businaro
- Istituto di Fotonica e Nanotecnologie-CNR, Via Cineto Romano 42, 00156 Rome, Italy
| | - Marco De Spirito
- Istituto di Fisica, Universitá Cattolica SC, L.go Francesco Vito 1, 00168 Rome, Italy
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