1
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Brahana P, Patel R, Bharti B. Surface Science View of Perfluoroalkyl Acids (PFAAs) in the Environment. ACS ENVIRONMENTAL AU 2024; 4:173-185. [PMID: 39035868 PMCID: PMC11258754 DOI: 10.1021/acsenvironau.3c00079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/19/2024] [Accepted: 04/19/2024] [Indexed: 07/23/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) constitute a notorious category of anthropogenic contaminants, detected across various environmental domains. Among these PFAS, perfluoroalkyl acids (PFAAs) stand out as a focal point in discussions due to their historical industrial utilization and environmental prominence. Their extensive industrial adoption is a direct consequence of their remarkable stability and outstanding amphiphilic properties. However, these very traits that have made PFAAs industrially desirable also render them environmentally catastrophic, leading to adverse consequences for ecosystems. The amphiphilic nature of PFAAs has made them highly unique in the landscape of anthropogenic contaminants and, thereby, difficult to study. We believe that well-established principles from surface science can connect the amphiphilic nature of PFAAs to their accumulation and transport in the environment. Specifically, we discuss the role of interfacial science in describing the stability, interfacial uptake (air-liquid and solid-liquid), and wetting capability of PFAAs. Surface science principles can provide new insights into the environmental fate of PFAAs, as well as provide context on their deleterious effects on both the environment and human health.
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Affiliation(s)
- Philip
J. Brahana
- Cain Department of Chemical
Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Ruchi Patel
- Cain Department of Chemical
Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Bhuvnesh Bharti
- Cain Department of Chemical
Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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2
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DeFlorio W, Zaza A, Arcot Y, Min Y, Castillo A, Taylor M, Cisneros-Zevallos L, Akbulut MES. Bioinspired Superhydrophobic Nanocoating Based on Polydopamine and Nanodiamonds to Mitigate Bacterial Attachment to Polyvinyl Chloride Surfaces in Food Industry Environments. Ind Eng Chem Res 2024; 63:6235-6248. [PMID: 38617109 PMCID: PMC11009964 DOI: 10.1021/acs.iecr.3c04230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 04/16/2024]
Abstract
Polyvinyl chloride (PVC) is commonly utilized as a food-contact surface by the food industry for processing and storage purposes due to its durability, ease of fabrication, and cost-effectiveness. Herein, we report a composite coating for the superhydrophobization of PVC without the use of polyfluoroalkyl chemistry. This coating rendered the PVC superhydrophobic, exhibiting a static water contact angle of 151.9 ± 0.7° and a contact angle hysteresis of only 3.1 ± 1.0°. The structure of this composite coating, consisting of polydopamine, nanodiamonds, and an alkyl silane, was investigated by utilizing both scanning electron microscopy and atomic force microscopy. Surface chemistry was probed using attenuated total reflectance-Fourier transform infrared, and the surface wetting behavior was thoroughly characterized using both static and dynamic water contact angle measurements. It was demonstrated that the superhydrophobic PVC was cleanable using a food-grade surfactant, becoming wet in contact with high concentration surfactant solutions, but regaining its nonwetting property upon rinsing with water. It was demonstrated that the coating produced a 2.1 ± 0.1 log10 reduction (99.2%) in the number of Escherichia coli O157:H7 cells and a 2.2 ± 0.1 log10 reduction (99.3%) in the number of Salmonella enterica Typhimurium cells that were able to adsorb onto PVC surfaces over a 24 h period. The use of this fluorine-free superhydrophobic coating on PVC equipment, such as conveyor belts within food production facilities, may help to mitigate bacterial cross-contamination and curb the spread of foodborne illnesses.
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Affiliation(s)
- William DeFlorio
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Abdulla Zaza
- Department
of Chemical Engineering, Texas A&M University
at Qatar, Doha 23874, Qatar
| | - Yashwanth Arcot
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Younjin Min
- Depart
of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Alejandro Castillo
- Department
of Food Science and Technology, Texas A&M
University, College Station, Texas 77843, United States
| | - Matthew Taylor
- Department
of Animal Science, Texas A&M University, College Station, Texas 77843, United States
| | - Luis Cisneros-Zevallos
- Department
of Horticultural Sciences, Texas A&M
University, College Station, Texas 77843, United States
| | - Mustafa E. S. Akbulut
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
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3
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DeFlorio W, Liu S, Arcot Y, Ulugun B, Wang X, Min Y, Cisneros-Zevallos L, Akbulut M. Durable superhydrophobic coatings for stainless-steel: An effective defense against Escherichia coli and Listeria fouling in the post-harvest environment. Food Res Int 2023; 173:113227. [PMID: 37803546 DOI: 10.1016/j.foodres.2023.113227] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 10/08/2023]
Abstract
Increasing concerns revolve around bacterial cross-contamination of leafy green vegetables via food-contact surfaces. Given that stainless-steel is among the commonly used food-contact surfaces, this study reports a coating strategy enhancing its hygiene and microbiological safety through an antifouling approach via superhydrophobicity. The developed method involves growing a nickel-nanodiamond nanocomposite film on 304 stainless-steel via electroplating and sequential functionalization of the outer surface layer with nonpolar organosilane molecules via polydopamine moieties. The resultant superhydrophobic stainless-steel surfaces had a static water contact angle of 156.3 ± 1.9° with only 2.3 ± 0.5° contact angle hysteresis. Application of the coating to stainless-steel was demonstrated to yield 2.3 ± 0.6 log10 and 2.0 ± 0.9 log10 reductions in the number of adherent gram-negative Escherichia coli O157:H7 and gram-positive Listeria innocua cells, respectively. These population reductions were shown to be statistically significant (α = 0.05). Coated stainless-steel also resisted fouling when contacted with contaminated romaine lettuce leaves and maintained significant non-wetting character when abraded with sand or contacted with high concentration surfactant solutions. The incorporation of superhydrophobic stainless-steel surfaces into food processing equipment used for washing and packaging leafy green vegetables has the potential to mitigate the transmission of pathogenic bacteria within food production facilities.
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Affiliation(s)
- William DeFlorio
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Shuhao Liu
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Yashwanth Arcot
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Beril Ulugun
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Xunhao Wang
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA
| | - Younjin Min
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA
| | - Luis Cisneros-Zevallos
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Mustafa Akbulut
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA.
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4
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Chowdhury P, Jha A, Bhandary D. Influence of Temperature-Guided SAM Growth on Wetting and Its Mass Transfer Models. J Phys Chem B 2023; 127:8208-8215. [PMID: 37703434 DOI: 10.1021/acs.jpcb.3c04173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
The formation and growth of self-assembled monolayers (SAMs) composed of amphiphiles have garnered significant attention due to their diverse technical applications. This article reports the findings of molecular dynamics simulations aimed at elucidating the intricate relationship between the wetting behavior of amphiphiles, specifically n-alkanols, and the growth of their SAMs on a mica surface under varying temperature conditions. The investigation quantifies the structural characteristics of the formed SAMs, including density profiles, in-plane radial distribution functions, order parameters, and end-to-end length distributions of n-alkanol molecules within the SAM. Thermodynamic properties, such as the second virial coefficient and excess entropy, are examined in relation to temperature and time. The growth of the SAM is assessed by analyzing characteristic time scales at different temperatures and in-plane diffusion of n-alkanol molecules and utilizing classical theories of mass transfer to quantify the growth rate as a function of temperature. These results are then correlated with changes in the contact angle and spreading coefficient of n-alkanol droplets on the mica surface over time, providing insights into the impact of SAM growth on the wetting behavior and the mass transfer model of such systems.
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Affiliation(s)
- Prateek Chowdhury
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) Varanasi, Varanasi, UP 221005, India
| | - Ayush Jha
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) Varanasi, Varanasi, UP 221005, India
| | - Debdip Bhandary
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) Varanasi, Varanasi, UP 221005, India
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5
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Hisa T, Kanno Y, Shirai T, Oshiki T, Mizuhata Y, Tokitoh N, Fukumoto H, Agou T. Synthesis and characterization of a polystyrene-type polymer bearing a cyclic perfluoroalkylene group. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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6
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Advances in the Fabrication and Characterization of Superhydrophobic Surfaces Inspired by the Lotus Leaf. Biomimetics (Basel) 2022; 7:biomimetics7040196. [PMID: 36412724 PMCID: PMC9680393 DOI: 10.3390/biomimetics7040196] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/28/2022] [Accepted: 11/02/2022] [Indexed: 11/12/2022] Open
Abstract
Nature has proven to be a valuable resource in inspiring the development of novel technologies. The field of biomimetics emerged centuries ago as scientists sought to understand the fundamental science behind the extraordinary properties of organisms in nature and applied the new science to mimic a desired property using various materials. Through evolution, living organisms have developed specialized surface coatings and chemistries with extraordinary properties such as the superhydrophobicity, which has been exploited to maintain structural integrity and for survival in harsh environments. The Lotus leaf is one of many examples which has inspired the fabrication of superhydrophobic surfaces. In this review, the fundamental science, supported by rigorous derivations from a thermodynamic perspective, is presented to explain the origin of superhydrophobicity. Based on theory, the interplay between surface morphology and chemistry is shown to influence surface wetting properties of materials. Various fabrication techniques to create superhydrophobic surfaces are also presented along with the corresponding advantages and/or disadvantages. Recent advances in the characterization techniques used to quantify the superhydrophobicity of surfaces is presented with respect to accuracy and sensitivity of the measurements. Challenges associated with the fabrication and characterization of superhydrophobic surfaces are also discussed.
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7
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Wettability of MXene films. J Colloid Interface Sci 2022; 622:759-768. [DOI: 10.1016/j.jcis.2022.04.135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 12/26/2022]
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8
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Milnes-Smith E, Stone CA, Willis CR, Perkin S. Surface Reconstruction of Fluoropolymers in Liquid Media. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4657-4668. [PMID: 35395153 PMCID: PMC9097541 DOI: 10.1021/acs.langmuir.2c00198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/25/2022] [Indexed: 06/14/2023]
Abstract
Surface reconstruction is the rearrangement of atoms or molecules at an interface in response to a stimulus, driven by lowering the overall free energy of the system. Perfluoroalkyl acrylate polymers with short side chains undergo reconstruction at room temperature when exposed to water. Here, we use contact angle aging to examine the liquid- and temperature- dependency of surface reconstruction of plasma polymerized perfluoroalkyl acrylates. We use a first order kinetic model to examine the dynamics of reconstructive processes. Our results show that, above the bulk melting point of the polymers, the contact angles of both polar and nonpolar (hydrocarbon) liquids show a time dependency well fit by the model. We conclude that surface reconstruction can be driven by the preferential segregation of hydrocarbon and fluorocarbon moieties as well as by polar interactions. This has implications in terms of using fluorocarbons to design oleophobic surfaces (and vice versa) and in terms of designing fluorocarbon and/or hydrocarbon surfaces with switchable wettability.
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Affiliation(s)
- Eleanor Milnes-Smith
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Corinne A. Stone
- Defence
Science and Technology Laboratory, Porton Down, Salisbury,
Wiltshire SP4 0JQ, United
Kingdom
| | - Colin R. Willis
- Defence
Science and Technology Laboratory, Porton Down, Salisbury,
Wiltshire SP4 0JQ, United
Kingdom
| | - Susan Perkin
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
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9
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Li C, Xu G, Wang L, Li J, Lu H. Tribological properties of graphene oxide and polyethylene glycol composites under dry friction and oil lubrication conditions. J Appl Polym Sci 2021. [DOI: 10.1002/app.51935] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Chengzhi Li
- Group of Mechanical and Biomedical Engineering, Xi'an Key Laboratory of Modern Intelligent Textile Equipment, College of Mechanical & Electronic Engineering Xi'an Polytechnic University Xi'an China
| | - Guangshen Xu
- Group of Mechanical and Biomedical Engineering, Xi'an Key Laboratory of Modern Intelligent Textile Equipment, College of Mechanical & Electronic Engineering Xi'an Polytechnic University Xi'an China
| | - Lisha Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xi'an Jiaotong University, Health Science Center Xi'an Jiaotong University Xi'an China
| | - Jianhui Li
- High‐end Functional Materials Research Center Chemistry and Chemical Engineering Guangdong Laboratory Shantou China
| | - Hailin Lu
- Group of Mechanical and Biomedical Engineering, Xi'an Key Laboratory of Modern Intelligent Textile Equipment, College of Mechanical & Electronic Engineering Xi'an Polytechnic University Xi'an China
- Taizhou Medical New & Hi‐Tech industrial Development Zone Taizhou China
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10
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Günal G, Okan M, Gokcen D, Caykara T, Aydin HM. Microwave-Assisted Synthesis of Stretchable and Transparent Poly(Ethyleneglycol-Sebacate) Elastomers with Autonomous Self-Healing and Capacitive Properties. Soft Robot 2021; 8:262-272. [PMID: 32552442 PMCID: PMC8236389 DOI: 10.1089/soro.2019.0148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Introducing functional synthetic biomaterials to the literature became quite essential in biomedical technologies. For the growth of novel biomedical engineering approaches, progressive functional properties as well as the robustness of the manufacturing processes are essential. By using acid-induced epoxide ring-opening polymerizations through catalysts, a wide variety of biodegradable and functionalized biomaterials can be synthesized. Sebacic acid (SA) and poly(ethylene glycol) diglycidyl ether (PEGDGE) are amongst the FDA-approved biocompatible materials. In this study, we focused on the rapid synthesis of caffeine-catalyzed self-healable elastomer via a facile microwave-assisted synthesis route. The elastomer prepared can be used in various applications, including tactile sensors, wearable electronics, and soft robotics. SA and PEGDGE were catalyzed in the presence of caffeine under microwave irradiation followed by crosslinking in vacuo, yielding an elastomeric material. The chemical characterizations of the obtained elastomer were carried out. The resulting material is transparent, highly stretchable, and has capacitive and self-healing properties even at room temperature. The material developed can be easily applied for the aforementioned applications.
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Affiliation(s)
- Gülçin Günal
- Bioengineering Division, Institute of Science, Hacettepe University, Ankara, Turkey
| | - Meltem Okan
- Department of Micro and Nanotechnology, Graduate School of Natural and Applied Sciences, Middle East Technical University, Ankara, Turkey
| | - Dincer Gokcen
- Department of Electrical and Electronics Engineering, Faculty of Engineering, Hacettepe University, Ankara, Turkey
| | - Tuncer Caykara
- Department of Chemistry, Faculty of Science, Gazi University, Ankara, Turkey
| | - Halil Murat Aydin
- Bioengineering Division, Institute of Science, Hacettepe University, Ankara, Turkey
- Centre for Bioengineering, Hacettepe University, Ankara, Turkey
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11
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Krathumkhet N, Ujihara M, Imae T. Self-standing films of octadecylaminated-TEMPO-oxidized cellulose nanofibrils with antifingerprint properties. Carbohydr Polym 2021; 256:117536. [PMID: 33483052 DOI: 10.1016/j.carbpol.2020.117536] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/02/2020] [Accepted: 12/15/2020] [Indexed: 10/22/2022]
Abstract
Self-standing films of cellulose nanofibril derivatives were prepared via oxidation by the 2,2,6,6-tetramethyl-1-piperidinyloxy radical and amidation with octadecylamine (ODA). The transparency and rigidity of the films decreased and their flexibility increased as the amide/carboxyl ratio increased. The introduction of the ODA also resulted in rising contact angles of water (from 43.5° to 117°) and oleic acid (from 22.5° to 57.1°). Furthermore, the films exhibited unique oil repellency: a drop of hexadecane slipped without tailing on the surface modified by ODA. This phenomenon was observed after moderate modification (water contact angle: 95-114°) and was absent for the films with the lowest and highest extents of modification. Then, the antifingerprint property of the films was examined by means of the powder test, and a reduction in fingerprints on the films was demonstrated. These results suggest the usefulness of developing transparent, self-standing oil-repellent films without perfluorinated compounds for antifingerprint and other antifouling applications.
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Affiliation(s)
- Nattinee Krathumkhet
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, 43 Section 4, Keelung Road, Taipei, 10607, Taiwan, ROC
| | - Masaki Ujihara
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, 43 Section 4, Keelung Road, Taipei, 10607, Taiwan, ROC.
| | - Toyoko Imae
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, 43 Section 4, Keelung Road, Taipei, 10607, Taiwan, ROC; Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Section 4, Keelung Road, Taipei, 10607, Taiwan, ROC; Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43 Section 4, Keelung Road, Taipei, 10607, Taiwan, ROC
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12
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Chang H, Liu B, Zhang Z, Pawar R, Yan Z, Crittenden JC, Vidic RD. A Critical Review of Membrane Wettability in Membrane Distillation from the Perspective of Interfacial Interactions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1395-1418. [PMID: 33314911 DOI: 10.1021/acs.est.0c05454] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Hydrophobic membranes used in membrane distillation (MD) systems are often subject to wetting during long-term operation. Thus, it is of great importance to fully understand factors that influence the wettability of hydrophobic membranes and their impact on the overall separation efficiency that can be achieved in MD systems. This Critical Review summarizes both fundamental and applied aspects of membrane wetting with particular emphasis on interfacial interaction between the membrane and solutes in the feed solution. First, the theoretical background of surface wetting, including the relationship between wettability and interfacial interaction, definition and measurement of contact angle, surface tension, surface free energy, adhesion force, and liquid entry pressure, is described. Second, the nature of wettability, membrane wetting mechanisms, influence of membrane properties, feed characteristics and operating conditions on membrane wetting, and evolution of membrane wetting are reviewed in the context of an MD process. Third, specific membrane features that increase resistance to wetting (e.g., superhydrophobic, omniphobic, and Janus membranes) are discussed briefly followed by the comparison of various cleaning approaches to restore membrane hydrophobicity. Finally, challenges with the prevention of membrane wetting are summarized, and future work is proposed to improve the use of MD technology in a variety of applications.
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Affiliation(s)
- Haiqing Chang
- Key Laboratory of Deep Earth Science and Engineering (Ministry of Education), College of Architecture and Environment, Sichuan University, Chengdu 610207, China
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Baicang Liu
- Key Laboratory of Deep Earth Science and Engineering (Ministry of Education), College of Architecture and Environment, Sichuan University, Chengdu 610207, China
| | - Zhewei Zhang
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Ritesh Pawar
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Zhongsen Yan
- College of Civil Engineering, Fuzhou University, Fujian, 350116, China
| | - John C Crittenden
- Brook Byers Institute for Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Radisav D Vidic
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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13
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Liu S, Bae M, Hao L, Oh JK, White AR, Min Y, Cisneros-Zevallos L, Akbulut M. Bacterial Antifouling Characteristics of Helicene-Graphene Films. NANOMATERIALS 2021; 11:nano11010089. [PMID: 33401616 PMCID: PMC7830421 DOI: 10.3390/nano11010089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/20/2020] [Accepted: 01/01/2021] [Indexed: 12/12/2022]
Abstract
Herein, we describe interfacially-assembled [7]helicene films that were deposited on graphene monolayer using the Langmuir-Schaefer deposition by utilizing the interactions of nonplanar (helicene) and planar (graphene) π–π interactions as functional antifouling coatings. Bacterial adhesion of Staphylococcus aureus on helicene—graphene films was noticeably lower than that on bare graphene, up to 96.8% reductions in bacterial adhesion. The promising bacterial antifouling characteristics of helicene films was attributed to the unique molecular geometry of helicene, i.e., nano-helix, which can hinder the nanoscale bacterial docking processes on a surface. We envision that helicene—graphene films may eventually be used as protective coatings against bacterial antifouling on the electronic components of clinical and biomedical devices.
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Affiliation(s)
- Shuhao Liu
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA; (S.L.); (M.B.)
| | - Michael Bae
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA; (S.L.); (M.B.)
| | - Li Hao
- School of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China;
| | - Jun Kyun Oh
- Department of Polymer Science and Engineering, Dankook University, 152 Jukjeon-ro, Suji-gu, Yongin-si 16890, Korea;
| | - Andrew R. White
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA; (A.R.W.); (Y.M.)
| | - Younjin Min
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA; (A.R.W.); (Y.M.)
| | - Luis Cisneros-Zevallos
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA;
| | - Mustafa Akbulut
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA; (S.L.); (M.B.)
- Correspondence:
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14
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Pillai S, Santana A, Das R, Shrestha BR, Manalastas E, Mishra H. A molecular to macro level assessment of direct contact membrane distillation for separating organics from water. J Memb Sci 2020. [DOI: 10.1016/j.memsci.2020.118140] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Xie Y, Khishvand M, Piri M. Wettability of Calcite Surfaces: Impacts of Brine Ionic Composition and Oil Phase Polarity at Elevated Temperature and Pressure Conditions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6079-6088. [PMID: 32388994 DOI: 10.1021/acs.langmuir.0c00367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The interactions among the polar components of oil, aqueous phase ions, and carbonate minerals, as well as their subsequent effects on surface wettability, can significantly impact the fluid distribution and recovery in a hydrocarbon reservoir. In this study, we investigate the adsorption/desorption of molecules from oils with different levels of polarity on calcite surfaces during different displacement processes under elevated pressure and temperature conditions. We measured dynamic contact angles (CA) on untreated and aged calcite substrates using brines with different salinities and compositions and model oils, that is, mixtures of varying concentrations of stearic acid (SA) and n-decane. In particular, the impacts of the concentrations of Ca2+, SO42-, and OH- ions on the adsorption phenomena were explored. For the nonpolar oil, increasing brine salinity or removing Ca2+ ions from the aqueous phase impacted the potentials of oil-brine and brine-mineral interfaces and shifted the wettability of calcite surface toward more water-wet conditions. In the presence of polar oil, the adsorption of the polar components controls the surface wettability. Higher concentrations of Ca2+/SO42- could facilitate/obstruct the polar component adsorption and thus increase/decrease the dynamic oil-water CAs. It is also observed that the brine salinity does not impact the wettability if excess SA is added to the oil phase, that is, if the oil phase is strongly polar. Moreover, the adsorption of SA on the calcite surface under experimental conditions is found to be reversible during the displacement events. The surface energy calculation for the adsorption process indicates that the surface coverage of calcite by SA is more sensitive to the presence of Ca2+ in brine than the concentration of polar components in oil. We also conducted several experiments on calcite substrates aged with SA. The measurements demonstrate that the adsorbed SA molecules are detached when the aged mineral surface is exposed to a lower-salinity brine at high temperatures, and the SA molecules could be adsorbed back on the surface once the displacement is halted.
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Affiliation(s)
- Yun Xie
- Center of Innovation for Flow through Porous Media, Department of Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Mahdi Khishvand
- Center of Innovation for Flow through Porous Media, Department of Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Mohammad Piri
- Center of Innovation for Flow through Porous Media, Department of Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071, United States
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16
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Seo D, Shim J, Lee C, Nam Y. Brushed lubricant-impregnated surfaces (BLIS) for long-lasting high condensation heat transfer. Sci Rep 2020; 10:2959. [PMID: 32076000 PMCID: PMC7031390 DOI: 10.1038/s41598-020-59683-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 01/16/2020] [Indexed: 11/08/2022] Open
Abstract
Recently, lubricant-impregnated surfaces (LIS) have emerged as a promising condenser surface by facilitating the removal of condensates from the surface. However, LIS has the critical limitation in that lubricant oil is depleted along with the removal of condensates. Such oil depletion is significantly aggravated under high condensation heat transfer. Here we propose a brushed LIS (BLIS) that can allow the application of LIS under high condensation heat transfer indefinitely by overcoming the previous oil depletion limit. In BLIS, a brush replenishes the depleted oil via physical contact with the rotational tube, while oil is continuously supplied to the brush by capillarity. In addition, BLIS helps enhance heat transfer performance with additional route to droplet removal by brush sweeping. By applying BLIS, we maintain the stable dropwise condensation mode for > 48 hours under high supersaturation levels along with up to 61% heat transfer enhancement compared to hydrophobic surfaces.
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Affiliation(s)
- Donghyun Seo
- Department of Mechanical Engineering, Kyung Hee University, Yongin, 446-701, South Korea
| | - Jaehwan Shim
- Department of Mechanical Engineering, Kyung Hee University, Yongin, 446-701, South Korea
| | - Choongyeop Lee
- Department of Mechanical Engineering, Kyung Hee University, Yongin, 446-701, South Korea.
| | - Youngsuk Nam
- Department of Mechanical Engineering, Kyung Hee University, Yongin, 446-701, South Korea.
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17
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Seo D, Shim J, Moon B, Lee K, Lee J, Lee C, Nam Y. Passive Anti-Flooding Superhydrophobic Surfaces. ACS APPLIED MATERIALS & INTERFACES 2020; 12:4068-4080. [PMID: 31891474 DOI: 10.1021/acsami.9b17943] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Superhydrophobic (SHPo) surfaces can provide high condensation heat transfer due to facilitated droplet removal. However, such high performance has been limited to low supersaturation conditions due to surface flooding. Here, we quantify flooding resistance defined as the rate of increase in the fraction of water-filled cavities with respect to the supersaturation level. Based on the quantitative understanding of surface flooding, we suggest effective anti-flooding strategies through tailoring the nanoscale coating heterogeneity and structure length scale. Experimental verification is conducted using CuO nanostructures having different length scales combined with hydrophobic coatings with different nanoscale heterogeneities. The proposed anti-flooding SHPo can provide a ∼130% enhanced average heat transfer coefficient with ∼14% larger supersaturation range for droplet jumping compared to a previous CuO SHPo. The proposed anti-flooding parameter and the scalable SHPo will help develop high-performance condensers for real-world applications operating in a wide range of supersaturation levels.
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Affiliation(s)
- Donghyun Seo
- Department of Mechanical Engineering , Kyung Hee University , Yongin 446-701 , Korea
| | - Jaehwan Shim
- Department of Mechanical Engineering , Kyung Hee University , Yongin 446-701 , Korea
| | - Byungyun Moon
- Department of Mechanical Engineering , Kyung Hee University , Yongin 446-701 , Korea
| | - Kyungjun Lee
- Department of Mechanical Engineering , Kyung Hee University , Yongin 446-701 , Korea
| | - Jooyoung Lee
- Department of Mechanical Engineering , Kyung Hee University , Yongin 446-701 , Korea
| | - Choongyeop Lee
- Department of Mechanical Engineering , Kyung Hee University , Yongin 446-701 , Korea
| | - Youngsuk Nam
- Department of Mechanical Engineering , Kyung Hee University , Yongin 446-701 , Korea
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18
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Tadmor R, Baksi A, Gulec S, Jadhav S, N'guessan HE, Sen K, Somasi V, Tadmor M, Wasnik P, Yadav S. Drops That Change Their Mind: Spontaneous Reversal from Spreading to Retraction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15734-15738. [PMID: 31436428 DOI: 10.1021/acs.langmuir.9b02592] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A liquid drop may spread faster on surfaces when surfactants are added. Here we show that after some time the spreading in such systems can, under certain conditions, spontaneously reverse to retraction and the droplet pulls itself back, receding from areas it has just recently wetted, elevating its center of mass in a jerklike motion. The duration from drop placement to the onset of retraction ranges from hours to less than a second primarily as a function of surfactant concentration. When the retraction is asymmetric, it results in drop motion, and when it is symmetric, the mass of the drop collects itself on its spot. This phenomenon, which was predicted theoretically in 2014, is apparently a general one for drops with surfactants; however, other factors, such as evaporation and contamination, prevented its observance so far.
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Affiliation(s)
- R Tadmor
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
- Department of Mechanical Engineering , Ben Gurion University , Beer Sheva , Israel
| | - A Baksi
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - S Gulec
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - S Jadhav
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - H E N'guessan
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - K Sen
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - V Somasi
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - M Tadmor
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - P Wasnik
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - S Yadav
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
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19
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Contact angles: From past mistakes to new developments through liquid-solid adhesion measurements. Adv Colloid Interface Sci 2019; 267:1-14. [PMID: 30861389 DOI: 10.1016/j.cis.2019.02.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 11/22/2022]
Abstract
A contact angle observed for a liquid-solid system is not necessarily a unique value and a few different contact angles need to be carefully considered in relation to liquid spreading, adhesion and phase separation. Despite the conceptual simplicity of the contact angle and over 200 years of investigation, interpretations of experimental contact angles remain controversial, and mistakes are quite common. Here, the physics behind equilibrium contact angles are restated and their misuse in modern literature is briefly discussed. Selected advances made in the 20th century that shaped current interpretations of experimental contact angles are also critically reviewed and evaluated. Understanding of contact angles for liquids on solids has improved in the last two decades and this progress is driven by advanced imaging techniques and improved methodologies in contact angle measurements, often in tandem with direct force measurements for liquid droplets in contact with solids. In our laboratory, a microelectronic balance system is employed to measure the force of liquid droplet spontaneous spreading and the water-solid adhesion forces at different stages of droplet retraction and separation. A microbalance equipped with a camera and data acquisition software measures these forces directly, monitors droplet-surface separation including distances over which the droplet stretches, and collects optical images simultaneously. The images are used to analyze capillary and surface tension forces based on measured droplet dimensions, shapes of surfaces and values of contact angles. These force measurements have significantly furthered our fundamental understanding of advancing, receding and most stable contact angles, and their correlations with adhesion, and are summarized in this review.
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20
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Gulec S, Yadav S, Das R, Bhave V, Tadmor R. The Influence of Gravity on Contact Angle and Circumference of Sessile and Pendant Drops has a Crucial Historic Aspect. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5435-5441. [PMID: 30839217 DOI: 10.1021/acs.langmuir.8b03861] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Normally, pendant drops adapt contact angles that are closer to 90° than their sessile analogues. This is due to the drop's weight that pulls the pendant drop and straightens its contact angles. In this paper, we show a case in which the opposite happens: sessile drops that adapt contact angles that are closer to 90° than their pendant analogues. To achieve these peculiar states, one needs to increase the effective gravity on the drops and then relax it again to 1 g. Apparently, this and other phenomena depend not only on the direction of the gravitational force but also on the drop's history. We show that the drop's contact angle (and resultant area) is affected by two types of histories: short-term history and long-term history. For example, if we gradually increase the effective gravity on the drop, decrease it back to 1 g, and then repeat this cycle again and again, we see that the first cycle is drastically different, whereas other cycles approach a plateau in their behavior. In addition to drop's history, we explain these observations in terms of volume conservation, drop contact area, and pinning effect. This study may be generalized for other body forces such as electrical and magnetic or accelerating systems.
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Affiliation(s)
- Semih Gulec
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - Sakshi Yadav
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - Ratul Das
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - Vaibhav Bhave
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
| | - Rafael Tadmor
- Dan F. Smith Department of Chemical Engineering , Lamar University , Beaumont , Texas 77710 , United States
- Department of Mechanical Engineering , Ben Gurion University , Beer Sheva 8410501 , Israel
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21
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Wetting Properties of Polyetheretherketone Plasma Activated and Biocoated Surfaces. COLLOIDS AND INTERFACES 2019. [DOI: 10.3390/colloids3010040] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Polyetheretherketone (PEEK) biomaterial is a polymer which has been widely used since the early 90s as a material for human bone implant preparations. Nowadays it is increasingly used due to its high biocompatibility and easily modeling, as well as better mechanical properties and price compared to counterparts made of titanium or platinum alloys. In this paper, air low-temperature and pressure plasma was used to enhance PEEK adhesive properties as well as surface sterilization. On the activated polymeric carrier, biologically-active substances have been deposited with the Langmuir-Blodgett technique. Thereafter, the surface was characterized using optical profilometry, and wettability was examined by contact angle measuring. Next, the contact angle hysteresis (CAH) model was used to calculate the surface free energy of the modified surface of PEEK. The variations of wettability and surface free energy were observed depending on the deposited monolayer type and its components.
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22
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Antwi-Baah R, Liu H. Recent Hydrophobic Metal-Organic Frameworks and Their Applications. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E2250. [PMID: 30424526 PMCID: PMC6265769 DOI: 10.3390/ma11112250] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/02/2018] [Accepted: 11/08/2018] [Indexed: 12/12/2022]
Abstract
The focus of discussion of this review is the application of the most recent synthesized hydrophobic metal-organic frameworks (MOFs). The most promising hydrophobic MOFs are mentioned with their applications and discussed. The various MOFs considered are sub-sectioned into the main application areas, namely alcohol adsorption and oil/water-alcohol/water separation, gas separation and storage, and other applications such as self-cleaning and liquid marbles. Again, the methods of synthesis are briefly described, showing how the features of the end product aid in their applications. The efficiency of the MOF materials and synthesis methods are highlighted and briefly discussed. Lastly, the summary and outlook section concludes the write-up giving suggestions that would be useful to present-day researchers.
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Affiliation(s)
- Ruth Antwi-Baah
- School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China.
| | - Heyang Liu
- School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China.
- Zhejiang Provincial Key Lab for Chem. & Bio. Processing Technology of Farm Product, Hangzhou 310023, China.
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23
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Abstract
When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.
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Affiliation(s)
- Lasse Makkonen
- VTT Technical Research Centre of Finland, Espoo 02044 VTT, Finland
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24
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Kim K, Ryu JH, Kim J, Cho SJ, Liu D, Park J, Lee IK, Moody B, Zhou W, Albrecht J, Ma Z. Band-Bending of Ga-Polar GaN Interfaced with Al 2O 3 through Ultraviolet/Ozone Treatment. ACS APPLIED MATERIALS & INTERFACES 2017; 9:17576-17585. [PMID: 28447450 DOI: 10.1021/acsami.7b01549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Understanding the band bending at the interface of GaN/dielectric under different surface treatment conditions is critically important for device design, device performance, and device reliability. The effects of ultraviolet/ozone (UV/O3) treatment of the GaN surface on the energy band bending of atomic-layer-deposition (ALD) Al2O3 coated Ga-polar GaN were studied. The UV/O3 treatment and post-ALD anneal can be used to effectively vary the band bending, the valence band offset, conduction band offset, and the interface dipole at the Al2O3/GaN interfaces. The UV/O3 treatment increases the surface energy of the Ga-polar GaN, improves the uniformity of Al2O3 deposition, and changes the amount of trapped charges in the ALD layer. The positively charged surface states formed by the UV/O3 treatment-induced surface factors externally screen the effect of polarization charges in the GaN, in effect, determining the eventual energy band bending at the Al2O3/GaN interfaces. An optimal UV/O3 treatment condition also exists for realizing the "best" interface conditions. The study of UV/O3 treatment effect on the band alignments at the dielectric/III-nitride interfaces will be valuable for applications of transistors, light-emitting diodes, and photovoltaics.
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Affiliation(s)
- Kwangeun Kim
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Jae Ha Ryu
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Jisoo Kim
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Sang June Cho
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Dong Liu
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Jeongpil Park
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - In-Kyu Lee
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Baxter Moody
- HexaTech, Inc. , 991 Aviation Parkway, Morrisville, North Carolina 27560, United States
| | - Weidong Zhou
- Department of Electrical Engineering, University of Texas at Arlington , 701 S. Nedderman Drive, Arlington, Texas 76019, United States
| | - John Albrecht
- Department of Electrical and Computer Engineering, Michigan State University , 428 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Zhenqiang Ma
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
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25
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Tadmor R, Das R, Gulec S, Liu J, E N'guessan H, Shah M, S Wasnik P, Yadav SB. Solid-Liquid Work of Adhesion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:3594-3600. [PMID: 28121158 DOI: 10.1021/acs.langmuir.6b04437] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We establish a tool for direct measurements of the work needed to separate a liquid from a solid. This method mimics a pendant drop that is subjected to a gravitational force that is slowly increasing until the solid-liquid contact area starts to shrink spontaneously. The work of separation is then calculated in analogy to Tate's law. The values obtained for the work of separation are independent of drop size and are in agreement with Dupré's theory, showing that they are equal to the work of adhesion.
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Affiliation(s)
- Rafael Tadmor
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
| | - Ratul Das
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
| | - Semih Gulec
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
| | - Jie Liu
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
| | - Hartmann E N'guessan
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
| | - Meet Shah
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
| | - Priyanka S Wasnik
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
| | - Sakshi B Yadav
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont Texas 77710, United States
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26
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Terpiłowski K, Wiącek AE, Jurak M. Influence of nitrogen plasma treatment on the wettability of polyetheretherketone and deposited chitosan layers. ADVANCES IN POLYMER TECHNOLOGY 2017. [DOI: 10.1002/adv.21813] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Konrad Terpiłowski
- Department of Physical Chemistry - Interfacial Phenomena; Faculty of Chemistry; Maria Curie-Sklodowska University; Lublin Poland
| | - Agnieszka Ewa Wiącek
- Department of Physical Chemistry - Interfacial Phenomena; Faculty of Chemistry; Maria Curie-Sklodowska University; Lublin Poland
| | - Małgorzata Jurak
- Department of Physical Chemistry - Interfacial Phenomena; Faculty of Chemistry; Maria Curie-Sklodowska University; Lublin Poland
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27
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Abstract
The role of relative humidity (RH) on the wetting behavior of droplets of two [Rmim][NTf2] ionic liquids (ILs) on a mica surface was investigated and water vapor adsorption was found to enhance the ILs precursor film formation and droplet spreading.
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Affiliation(s)
- Zhantao Wang
- Key Laboratory of Optoelectronic Devices and Systems of MOE
- Institute of Optoelectronics
- Shenzhen University
- Shenzhen 518060
- China
| | - Fuxi Shi
- College of Mechanical and Electronic Engineering
- Northwest A&F University
- Yangling 712100
- China
| | - Cunlu Zhao
- Key Laboratory of Thermo-Fluid Science and Engineering of MOE
- School of Energy and Power Engineering
- Xi'an Jiaotong University
- Xi'an 710049
- China
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28
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Wang Y, Ma L, Xu X, Luo J. Expressions for the evaporation of sessile liquid droplets incorporating the evaporative cooling effect. J Colloid Interface Sci 2016; 484:291-297. [DOI: 10.1016/j.jcis.2016.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/06/2016] [Accepted: 09/06/2016] [Indexed: 11/29/2022]
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29
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Jurak M. Effect of Lauryl Gallate on Wetting Properties of Organized Thin Phospholipid Films on Mica. J Phys Chem B 2016; 120:6657-66. [DOI: 10.1021/acs.jpcb.6b02434] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Małgorzata Jurak
- Department of Physical Chemistry—Interfacial
Phenomena, Faculty of Chemistry, Maria Curie-Skłodowska University, Maria Curie-Skłodowska
Sq. 3, 20031 Lublin, Poland
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30
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Tadmor R, Wasnik PS, N'guessan HE, Tadmor R, Tadmor M. Inducing arbitrary vapor pressures, and quantifying leakages. AIChE J 2016. [DOI: 10.1002/aic.15329] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Rafael Tadmor
- Dan F. Smith Dept. of Chemical Engineering; Lamar University; Beaumont TX 77710
| | - Priyanka S. Wasnik
- Dan F. Smith Dept. of Chemical Engineering; Lamar University; Beaumont TX 77710
| | | | - Rafael Tadmor
- Dept. of Chemical Engineering; Technion, Israel Institute of Technology; Haifa Israel
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31
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Roy S, Suresh VM, Maji TK. Self-cleaning MOF: realization of extreme water repellence in coordination driven self-assembled nanostructures. Chem Sci 2016; 7:2251-2256. [PMID: 29910914 PMCID: PMC5977372 DOI: 10.1039/c5sc03676c] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/11/2015] [Indexed: 11/21/2022] Open
Abstract
Bio-inspired self-cleaning surfaces have found industrial applications in oil-water separation, stain resistant textiles, anti-biofouling paints in ships etc. Interestingly, self-cleaning metal-organic framework (MOF) materials having high water contact angles and corrosion resistance have not been realized so far. To address this issue, we have used the fundamentals of self-assembly to expose hydrophobic alkyl chains on a MOF surface. This decreases the surface free energy and hence increases hydrophobicity. Coordination directed self-assembly of dialkoxyoctadecyl-oligo-(p-phenyleneethynylene)dicarboxylate (OPE-C18 ) with ZnII in a DMF/H2O mixture leads to a three dimensional supramolecular porous framework {Zn(OPE-C18)·2H2O} (NMOF-1) with nanobelt morphology. Inherently superhydrophobic and self-cleaning NMOF-1 has high thermal and chemical stability. The periodic arrangement of 1D Zn-OPE-C18 chains with octadecyl alkyl chains projecting outward reduces the surface free energy leading to superhydrophobicity in NMOF-1 (contact angle: 160-162°). The hierarchical surface structure thus generated, enables NMOF-1 to mimic the lotus leaf in its self-cleaning property with an unprecedented tilt angle of 2°. Additionally, superhydrophobicity remains intact over a wide pH range (1-9) and under high ionic concentrations. We believe that such a development in this field will herald a new class of materials capable of water repellent applications.
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Affiliation(s)
- Syamantak Roy
- Molecular Materials Laboratory , Chemistry and Physics of Materials Unit , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore-560064 , India .
| | - Venkata M Suresh
- Molecular Materials Laboratory , Chemistry and Physics of Materials Unit , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore-560064 , India .
| | - Tapas Kumar Maji
- Molecular Materials Laboratory , Chemistry and Physics of Materials Unit , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore-560064 , India .
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32
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Hung KC, Hsu SH. Polymer surface interacts with calcium in aqueous media to induce stem cell assembly. Adv Healthc Mater 2015; 4:2186-94. [PMID: 26332827 DOI: 10.1002/adhm.201500374] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 07/27/2015] [Indexed: 01/16/2023]
Abstract
Bioinspired surface with functional group rearrangement abilities are highly desirable for designing functional materials. Calcium ion (Ca(2+) ) is a pivotal life element and the ion transport is tightly regulated through calcium channels. It is demonstrated here that Ca(2+) can be transported by polymer surface to induce cell assembly. A series of polyurethane materials is synthesized with different abilities to rearrange the surface functional groups in response to aqueous environment. It is observed that surface recruitment of carboxyl and amino groups from the bulk material can interact with Ca(2+) and facilitate its translocation from aqueous media into cells. The surface rearrangement of functional group triggers the calcium trafficking and turns on signals involving cell merging and assembly. This observation provides an insight on adjusting material-calcium interaction to design nature-inspired smart interfaces to induce cell organization and tissue regeneration.
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Affiliation(s)
- Kun-Che Hung
- Institute of Polymer Science and Engineering; National Taiwan University; Taipei 10617 Taiwan
| | - Shan-hui Hsu
- Institute of Polymer Science and Engineering; National Taiwan University; Taipei 10617 Taiwan
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33
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Controlling arbitrary humidity without convection. J Colloid Interface Sci 2015; 455:212-9. [DOI: 10.1016/j.jcis.2015.04.072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 04/23/2015] [Indexed: 01/24/2023]
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34
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Geometric Interpretation of Surface Tension Equilibrium in Superhydrophobic Systems. ENTROPY 2015. [DOI: 10.3390/e17074684] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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35
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Detailed statistical contact angle analyses; “slow moving” drops on inclining silicon-oxide surfaces. J Colloid Interface Sci 2015; 447:229-39. [DOI: 10.1016/j.jcis.2014.10.047] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 11/24/2022]
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36
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Cremaldi JC, Khosla T, Jin K, Cutting D, Wollman K, Pesika N. Interaction of oil drops with surfaces of different interfacial energy and topography. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3385-3390. [PMID: 25723337 DOI: 10.1021/acs.langmuir.5b00051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
During a marine oil spill, the oil can interact with and potentially wet a variety of surfaces such as corals, skin/shells of marine animals, and bird feathers. We present both qualitative and quantitative data for the interaction of a dodecane droplet submerged in water with surfaces varying in both surface energy and roughness. Flat, unstructured silicon surfaces with water in air contact angles of 0°, 43°, 66°, 87°, 96°, and 108° were tested first to obtain base readings, after which photolithography was used to introduce structured surfaces representative of marine biological systems. We find that the more hydrophilic a surface, the less prone it is to oil contamination. Also, the Cassie-Baxter approximation holds up for submerged oil in water systems and can be used to predict contact angles of oil on solid rough surfaces submerged in an aqueous environment. Furthermore, the addition of surface structure, even on strongly hydrophobic (oleophilic) surfaces, greatly reduced (≈75% reduction in F(adhesion)) a surface's affinity for oil.
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Affiliation(s)
- Joseph C Cremaldi
- †Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Tushar Khosla
- †Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Kejia Jin
- †Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
- ‡Intralox, New Orleans, Louisiana 70123, United States
| | - David Cutting
- †Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
- §Koch International, Witchita, Kansas 67220, United States
| | - Kristen Wollman
- †Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Noshir Pesika
- †Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
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37
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Kristiansen K, Stock P, Baimpos T, Raman S, Harada JK, Israelachvili JN, Valtiner M. Influence of molecular dipole orientations on long-range exponential interaction forces at hydrophobic contacts in aqueous solutions. ACS NANO 2014; 8:10870-10877. [PMID: 25289697 DOI: 10.1021/nn504687b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Strong and particularly long ranged (>100 nm) interaction forces between apposing hydrophobic lipid monolayers are now well understood in terms of a partial turnover of mobile lipid patches, giving rise to a correlated long-range electrostatic attraction. Here we describe similarly strong long-ranged attractive forces between self-assembled monolayers of carboranethiols, with dipole moments aligned either parallel or perpendicular to the surface, and hydrophobic lipid monolayers deposited on mica. We compare the interaction forces measured at very different length scales using atomic force microscope and surface forces apparatus measurements. Both systems gave a long-ranged exponential attraction with a decay length of 2.0 ± 0.2 nm for dipole alignments perpendicular to the surface. The effect of dipole alignment parallel to the surface is larger than for perpendicular dipoles, likely due to greater lateral correlation of in-plane surface dipoles. The magnitudes and range of the measured interaction forces also depend on the surface area of the probe used: At extended surfaces, dipole alignment parallel to the surface leads to a stronger attraction due to electrostatic correlations of freely rotating surface dipoles and charge patches on the apposing surfaces. In contrast, perpendicular dipoles at extended surfaces, where molecular rotation cannot lead to large dipole correlations, do not depend on the scale of the probe used. Our results may be important to a range of scale-dependent interaction phenomena related to solvent/water structuring on dipolar and hydrophobic surfaces at interfaces.
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Affiliation(s)
- Kai Kristiansen
- Department of Chemical Engineering, §Materials Research Laboratory, and ∥Materials Department, University of California , Santa Barbara, California 93106, United States
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Stocco A, Su G, Nobili M, In M, Wang D. In situ assessment of the contact angles of nanoparticles adsorbed at fluid interfaces by multiple angle of incidence ellipsometry. SOFT MATTER 2014; 10:6999-7007. [PMID: 24910076 DOI: 10.1039/c4sm00482e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Here multiple angle of incidence ellipsometry was successfully applied to in situ assess the contact angle and surface coverage of gold nanoparticles as small as 18 nm, coated with stimuli-responsive polymers, at water-oil and water-air interfaces in the presence of NaCl and NaOH, respectively. The interfacial adsorption of the nanoparticles was found to be very slow and took days to reach a fairly low surface coverage. For water-oil interfaces, in situ nanoparticle contact angles agree with the macroscopic equilibrium contact angles of planar gold surfaces with the same polymer coatings, whilst for water-air interfaces, significant differences have been observed.
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Affiliation(s)
- Antonio Stocco
- Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France.
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Ahn BK, Lee DW, Israelachvili JN, Waite JH. Surface-initiated self-healing of polymers in aqueous media. NATURE MATERIALS 2014; 13:867-72. [PMID: 25064231 DOI: 10.1038/nmat4037] [Citation(s) in RCA: 268] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 06/17/2014] [Indexed: 05/27/2023]
Abstract
Polymeric materials that intrinsically heal at damage sites under wet or moist conditions are urgently needed for biomedical and environmental applications. Although hydrogels with self-mending properties have been engineered by means of mussel-inspired metal-chelating catechol-functionalized polymer networks, biological self-healing in wet conditions, as occurs in self-assembled holdfast proteins in mussels and other marine organisms, is generally thought to involve more than reversible metal chelates. Here we demonstrate self-mending in metal-free water of synthetic polyacrylate and polymethacrylate materials that are surface-functionalized with mussel-inspired catechols. Wet self-mending of scission in these polymers is initiated and accelerated by hydrogen bonding between interfacial catechol moieties, and consolidated by the recruitment of other non-covalent interactions contributed by subsurface moieties. The repaired and pristine samples show similar mechanical properties, suggesting that the triggering of complete self-healing is enabled underwater by the formation of extensive catechol-mediated interfacial hydrogen bonds.
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Affiliation(s)
- B Kollbe Ahn
- Marine Science Institute, University of California, Santa Barbara, California 93106, USA
| | - Dong Woog Lee
- Chemical Engineering, University of California, Santa Barbara, California 93106, USA
| | - Jacob N Israelachvili
- Chemical Engineering, University of California, Santa Barbara, California 93106, USA
| | - J Herbert Waite
- Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106, USA
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40
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Hejazi V, Moghadam AD, Rohatgi P, Nosonovsky M. Beyond Wenzel and Cassie-Baxter: second-order effects on the wetting of rough surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9423-9429. [PMID: 25051526 DOI: 10.1021/la502143v] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The Wenzel and Cassie-Baxter models are almost exclusively used to explain the contact angle dependence of the structure of rough and patterned solid surfaces. However, these two classical models do not always accurately predict the wetting properties of surfaces since they fail to capture the effect of many interactions occurring during wetting, including, for example, the effect of the disjoining pressure and of crystal microstructure, grains, and defects. We call such effects the second-order effects and present here a model showing how the disjoining pressure isotherm can affect wettability due to the formation of thin liquid films. We measure water contact angles on pairs of metallic surfaces with nominally the same Wenzel roughness obtained by abrasion and by chemical etching. These two methods of surface roughening result in different rough surface structure, thus leading to different values of the contact angle, which cannot be captured by the Wenzel- and Cassie-type models. The chemical and physical changes that occur on the stainless steel and aluminum alloy surfaces as a result of intergranular corrosion, along with selective intermetallic dissolution, lead to a surface roughness generated on the nano- and microscales.
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Affiliation(s)
- Vahid Hejazi
- College of Engineering & Applied Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53211, United States
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41
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Pittoni PG, Lin CH, Yu TS, Lin SY. On the uniqueness of the receding contact angle: effects of substrate roughness and humidity on evaporation of water drops. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9346-9354. [PMID: 25029610 DOI: 10.1021/la501455d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Could a unique receding contact angle be indicated for describing the wetting properties of a real gas-liquid-solid system? Could a receding contact angle be defined if the triple line of a sessile drop is not moving at all during the whole measurement process? To what extent is the receding contact angle influenced by the intrinsic properties of the system or the measurement procedures? In order to answer these questions, a systematic investigation was conducted in this study on the effects of substrate roughness and relative humidity on the behavior of pure water drops spreading and evaporating on polycarbonate (PC) surfaces characterized by different morphologies. Dynamic, advancing, and receding contact angles were found to be strongly affected by substrate roughness. Specifically, a receding contact angle could not be measured at all for drops evaporating on the more rugged PC surfaces, since the drops were observed strongly pinning to the substrate almost until their complete disappearance. Substrate roughness and system relative humidity were also found responsible for drastic changes in the depinning time (from ∼10 to ∼60 min). Thus, for measurement observations not sufficiently long, no movement of the triple line could be noted, with, again, the failure to find a receding contact angle. Therefore, to keep using concepts such as the receding contact angle as meaningful specifications of a given gas-liquid-solid system, the imperative to carefully investigate and report the inner characteristics of the system (substrate roughness, topography, impurities, defects, chemical properties, etc.) is pointed out in this study. The necessity of establishing methodological standards (drop size, measurement method, system history, observation interval, relative humidity, etc.) is also suggested.
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Affiliation(s)
- Paola G Pittoni
- Department of Chemical Engineering National Taiwan University of Science and Technology , 43 Keelung Road, Section 4, Taipei 106, Taiwan
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Pujari SP, Scheres L, Marcelis ATM, Zuilhof H. Covalent Surface Modification of Oxide Surfaces. Angew Chem Int Ed Engl 2014; 53:6322-56. [DOI: 10.1002/anie.201306709] [Citation(s) in RCA: 583] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Indexed: 12/26/2022]
Affiliation(s)
- Sidharam P. Pujari
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (The Netherlands)
| | - Luc Scheres
- Surfix B.V. Dreijenplein 8, 6703 HB Wageningen (The Netherlands)
| | - Antonius T. M. Marcelis
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (The Netherlands)
| | - Han Zuilhof
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (The Netherlands)
- Department of Chemical and Materials Engineering, King Abdulaziz University, Jeddah (Saudi Arabia)
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Pujari SP, Scheres L, Marcelis ATM, Zuilhof H. Kovalente Oberflächenmodifikationen von Oxiden. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201306709] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Sidharam P. Pujari
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (Niederlande)
| | | | - Antonius T. M. Marcelis
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (Niederlande)
| | - Han Zuilhof
- Laboratory of Organic Chemistry, Wageningen University, P.O. Box 26, 6703 HB Wageningen (Niederlande)
- Department of Chemical and Materials Engineering, King Abdulaziz University, Jeddah (Saudi‐Arabien)
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Study on the wetting transition of a liquid droplet sitting on a square-array cosine wave-like patterned surface. J Colloid Interface Sci 2014; 418:8-19. [DOI: 10.1016/j.jcis.2013.12.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 11/12/2013] [Accepted: 12/04/2013] [Indexed: 11/18/2022]
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Paxson AT, Yagüe JL, Gleason KK, Varanasi KK. Stable dropwise condensation for enhancing heat transfer via the initiated chemical vapor deposition (iCVD) of grafted polymer films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:418-423. [PMID: 24114882 DOI: 10.1002/adma.201303065] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/13/2013] [Indexed: 06/02/2023]
Abstract
Ultra-thin copolymer films are deposited by initiated chemical deposition (iCVD) to investigate their performance under the condensation of water vapor. By forming a grafted interface between the coating and the substrate, the films exhibit stable dropwise condensation even when subjected to 100 °C steam. The applicability of the iCVD to complex substrate geometries is demonstrated on a copper condenser coil.
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Affiliation(s)
- Adam T Paxson
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
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46
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Tadmor R. Misconceptions in wetting phenomena. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15474-15475. [PMID: 24256467 DOI: 10.1021/la403578q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In a recent paper ('t Mannetje, D.; Banpurkar, A.; Koppelman, H.; Duits, M. H. G.; van den Ende, D.; Mugele, F. Electrically Tunable Wetting Defects Characterized by a Simple Capillary Force Sensor. Langmuir 2013, 29, 9944-9949), there are a few misconceptions regarding the interpretations of theories emanating from Shanahan and de Gennes in describing centrifugal adhesion balance (CAB) experiments, making their results seemingly contradictory to the theory. These are clarified here. We show that their results, if interpreted correctly, do not contradict the theories mentioned above.
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Affiliation(s)
- Rafael Tadmor
- Dan F. Smith Department of Chemical Engineering, Lamar University , Beaumont, Texas 77710, United States
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Séro L, Sanguinet L, Derbré S, Boury F, Brotons G, Dabos-Seignon S, Richomme P, Séraphin D. Fluorescent self-assembled monolayers of umbelliferone: a relationship between contact angle and fluorescence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:10423-10431. [PMID: 23879702 DOI: 10.1021/la401536p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Self-assembled monolayers (SAMs) that contain fluorophore units are nowadays widely used to tune surface properties and design new chemical sensor chips. It is well-known that the nature of the substrate may strongly interfere with the emission properties of the grafted molecules, but the organization of the monolayer may also have an important role. To study the influence of the SAM organization on the luminescence properties, we prepared different coumarin-based derivatives endowed with tethered chains of different lengths and elaborated the corresponding SAMs on glass slides. Besides SAM structural characterizations by atomic force microscopy and X-ray reflectivity, we carried out contact angle measurements and applied the Van Oss-Chaudhury-Good theory, which was rarely used previously for self-assembled monolayers. As expected, by increasing the tethered chain length, a higher surface coverage, a higher degree of organization, and a stronger molecular packing were observed. However, it appears to facilitate the self-quenching process, and thus, this strongly affects the fluorescent properties of the SAMs.
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Affiliation(s)
- Luc Séro
- PRES L'UNAM, Laboratoire MOLTECH-Anjou, Université d'Angers, CNRS-UMR 6200, 2 bd Lavoisier, 49045 Angers Cedex, France
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48
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Sun W, Zeng Q, Yu A, Kendall K. Calculation of normal contact forces between silica nanospheres. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:7825-7837. [PMID: 23687956 DOI: 10.1021/la401087j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this work, interaction forces between two silica nanospheres after contact, including the van der Waals (vdW) attraction, Born repulsion, and mechanical contact forces are studied by molecular dynamics (MD) simulations. The effects of interaction path (approach or departure), initial relative velocity, and relative orientations of two nanospheres are first examined. The results show that the interparticle forces are, to a large degree, independent of these variables. Then, emphasis is given to other important variables. At a small contact deformation, the size dependence of the vdW attraction and Born repulsion qualitatively agrees with the prediction based on the conventional theories, but this becomes vague upon further deformation due to the gradually flattened shape of deformed particles. An alternative approach is provided to calculate the interparticle vdW attraction and Born repulsion forces. Moreover, the MD simulations show that the Hertz model still holds to describe the mechanical contact force at low compression, which is obtained by subtracting the vdW attraction and Born repulsion forces from the total normal force. Comparisons with the Johnson-Kendall-Roberts (JKR) and Derjaguin-Muller-Toporov (DMT) models, in terms of force-displacement relationships and contact radius, show that the two models can be used to provide the first approximation, but there is some deviation from the MD simulated results. The origins of the quantitative difference are analyzed. New equations are formulated to estimate the interaction forces between silica nanospheres, which should be useful in the dynamic simulation of silica nanoparticle systems.
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Affiliation(s)
- Weifu Sun
- Laboratory for Simulation and Modeling of Particulate Systems, School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Xu W, Leeladhar R, Kang YT, Choi CH. Evaporation kinetics of sessile water droplets on micropillared superhydrophobic surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:6032-6041. [PMID: 23656600 DOI: 10.1021/la400452e] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Evaporation modes and kinetics of sessile droplets of water on micropillared superhydrophobic surfaces are experimentally investigated. The results show that a constant contact radius (CCR) mode and a constant contact angle (CCA) mode are two dominating evaporation modes during droplet evaporation on the superhydrophobic surfaces. With the decrease in the solid fraction of the superhydrophobic surfaces, the duration of a CCR mode is reduced and that of a CCA mode is increased. Compared to Rowan's kinetic model, which is based on the vapor diffusion across the droplet boundary, the change in a contact angle in a CCR (pinned) mode shows a remarkable deviation, decreasing at a slower rate on the superhydrophobic surfaces with less-solid fractions. In a CCA (receding) mode, the change in a contact radius agrees well with the theoretical expectation, and the receding speed is slower on the superhydrophobic surfaces with lower solid fractions. The discrepancy between experimental results and Rowan's model is attributed to the initial large contact angle of a droplet on superhydrophobic surfaces. The droplet geometry with a large contact angle results in a narrow wedge region of air along the contact boundary, where the liquid-vapor diffusion is significantly restricted. Such an effect becomes minor as the evaporation proceeds with the decrease in a contact angle. In both the CCR and CCA modes, the evaporative mass transfer shows the linear relationship between mass(2/3) and evaporation time. However, the evaporation rate is slower on the superhydrophobic surfaces, which is more significant on the surfaces with lower solid fractions. As a result, the superhydrophobic surfaces slow down the drying process of a sessile droplet on them.
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Affiliation(s)
- Wei Xu
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
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