1
|
Samanta R, Rowthu S. Can Microcavitated Slippery Surfaces Outperform Micropillared and Untextured? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 39377664 DOI: 10.1021/acs.langmuir.4c02956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/09/2024]
Abstract
Surface features' morphology is crucial in designing lubricant-infused slippery surfaces (LIS). Microcavities were hypothesized to provide lower physical pinning, reduced droplet normal adhesion, and superior lubricant retention as compared to micropillars and untextured surfaces. Micropillars and microcavities (h = 10 ± 3 μm, d = 8 ± 1 μm, p = 17 ± 3 μm, rw = 1.4 ± 0.2) were replicated on polydimethylsiloxane from Lotus leaf and were coated with 1000 cSt silicone oil films (530 nm-27 μm thick). Water wetting, water-oil thermodynamic stability, droplet's normal adhesion and oil shear drainage properties were investigated to evaluate the relative performance of microcavitated, micropillared and untextured LIS. For ≤7 μm thick oil films, cavitated and untextured LIS displayed superior slippery properties than micropillared LIS (16 ± 1°, 7 ± 1°, 30 ± 4° slide-off angles respectively). Also, normal adhesion is of the order: cavities < untextured < pillars, and smaller than their dry counterparts. Furthermore, the oil retention efficiency under the action of centrifugal forces and continuous shear flow of water is of the order: pillars > cavities > untextured. Thus, it can be concluded that microcavitated LIS can outperform micropillared and untextured LIS.
Collapse
Affiliation(s)
- Ratnadeep Samanta
- Materials Engineering Department, Indian Institute of Technology (IIT) Gandhinagar, Gujarat382055, India
| | - Sriharitha Rowthu
- Materials Engineering Department, Indian Institute of Technology (IIT) Gandhinagar, Gujarat382055, India
| |
Collapse
|
2
|
Huang TE, Lu Y, Wei Z, Li D, Li QY, Wang Z, Takahashi K, Orejon D, Zhang P. Ultrahigh Subcooling Dropwise Condensation Heat Transfer on Slippery Liquid-like Monolayer Grafted Surfaces. ACS APPLIED MATERIALS & INTERFACES 2024; 16:53285-53298. [PMID: 39295174 DOI: 10.1021/acsami.4c12220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/21/2024]
Abstract
Rapid and continuous droplet shedding is crucial for many applications, including thermal management, water harvesting, and microfluidics, among others. Superhydrophobic surfaces, though effective, suffer from droplet pinning at high subcooling temperature (Tsub). Conversely, slippery liquid-like surfaces covalently bonded with flexible hydrophobic molecules show high stability and low droplet adhesion attributed to their dense and ultrasmooth water repellent polymer chains, enhancing dropwise condensation and rapid shedding. In this work, linear poly(dimethylsiloxane) chains of various viscosities are covalently bonded onto silicon substrates to form thin and smooth monolayer coated surfaces. The formation of the monolayer is characterized by cryogenic transmission electron microscopy. On these surfaces a very low contact angle hysteresis is reported within wide surface temperature ranges as well as continuous dropwise condensation at ultrahigh Tsub of 60 K. In particular, one of the highest condensation heat fluxes of 1392.60 kW·m-2 and a heat transfer coefficient of 23.21 kW·m-2·K-1 at ultrahigh Tsub of 60 K is reported. The experimental heat transfer performance is further compared to the theoretical heat transfer via the individual droplets with the droplet distribution elucidated via both macroscopic observations as well as environmental scanning electron microscopy. Finally, only a mild decrease in the heat transfer coefficient of 20.3% after 100 h of condensation test at Tsub of 60 K is reported. Slippery liquid-like surfaces promote droplet shedding and sustain dropwise condensation at high Tsub without flooding empowered by the lower frictional forces, addressing challenges in heat transfer performance and durability.
Collapse
Affiliation(s)
- Ting-En Huang
- Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai 200240, China
| | - Yisheng Lu
- Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai 200240, China
| | - Zhaozhuo Wei
- Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai 200240, China
| | - Dawei Li
- Department of Aeronautics and Astronautics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Qin-Yi Li
- Department of Aeronautics and Astronautics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Zhenying Wang
- Department of Aeronautics and Astronautics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Koji Takahashi
- Department of Aeronautics and Astronautics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Daniel Orejon
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FD Scotland, United Kingdom
| | - Peng Zhang
- Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai 200240, China
| |
Collapse
|
3
|
Pupillo D, Bruns MP, Prado LH, Di Franco F, Böhringer D, Mazare A, Goldmann WH, Virtanen S, Santamaria M, Tesler AB. Corrosion Resistance of Biodegradable Zinc Surfaces Enhanced by UV-Grafted Polydimethylsiloxane Coating. ACS Biomater Sci Eng 2024; 10:4891-4900. [PMID: 39007167 DOI: 10.1021/acsbiomaterials.4c00503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Improved living conditions have led to an increase in life expectancy worldwide. However, as people age, the risk of vascular disease tends to increase due to the accumulation and buildup of plaque in arteries. Vascular stents are used to keep blood vessels open. Biodegradable stents are designed to provide a temporary support vessel that gradually degrades and is absorbed by the body, leaving behind healed blood vessels. However, biodegradable metals can suffer from reduced mechanical strength and/or inflammatory response, both of which can affect the rate of corrosion. Therefore, it is essential to achieve a controlled and predictable degradation rate. Here, we demonstrate that the corrosion resistance of biodegradable Zn surfaces is improved by electroless deposition of zinc hydroxystannate followed by UV-grafting with silicone oil (PDMS). Potentiodynamic polarization, electrochemical impedance spectroscopy, respiratory kinetic measurements, and long-term immersion in three simulated body fluids were applied. Although zinc hydroxystannate improves the corrosion resistance of Zn to some extent, it introduces a high surface area with hydroxyl units used to UV-graft PDMS molecules. Our results demonstrate that hydrophobic PDMS causes a 3-fold reduction in corrosion of Zn-based materials in biological environments and reduces cytotoxicity through the uncontrolled release of Zn ions.
Collapse
Affiliation(s)
- Davide Pupillo
- Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy
| | - Mark P Bruns
- Department of Materials Science and Engineering, Institute for Surface Science and Corrosion, Faculty of Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, Erlangen 91058, Germany
| | - Lucia H Prado
- Department of Materials Science and Engineering, Institute for Surface Science and Corrosion, Faculty of Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, Erlangen 91058, Germany
| | - Francesco Di Franco
- Dipartimento di Ingegneria, Università di Palermo, Viale delle Scienze, Ed.6, Palermo 90128, Italy
| | - David Böhringer
- Department of Physics, Biophysics Group, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 91, Erlangen 91052, Germany
| | - Anca Mazare
- Department of Materials Science and Engineering, Institute for Surface Science and Corrosion, Faculty of Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, Erlangen 91058, Germany
| | - Wolfgang H Goldmann
- Department of Physics, Biophysics Group, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 91, Erlangen 91052, Germany
| | - Sannakaisa Virtanen
- Department of Materials Science and Engineering, Institute for Surface Science and Corrosion, Faculty of Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, Erlangen 91058, Germany
| | - Monica Santamaria
- Dipartimento di Ingegneria, Università di Palermo, Viale delle Scienze, Ed.6, Palermo 90128, Italy
| | - Alexander B Tesler
- Department of Physics, Biophysics Group, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 91, Erlangen 91052, Germany
| |
Collapse
|
4
|
Hauer L, Naga A, Badr RGM, Pham JT, Wong WSY, Vollmer D. Wetting on silicone surfaces. SOFT MATTER 2024; 20:5273-5295. [PMID: 38952198 DOI: 10.1039/d4sm00346b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Silicone is frequently used as a model system to investigate and tune wetting on soft materials. Silicone is biocompatible and shows excellent thermal, chemical, and UV stability. Moreover, the mechanical properties of the surface can be easily varied by several orders of magnitude in a controlled manner. Polydimethylsiloxane (PDMS) is a popular choice for coating applications such as lubrication, self-cleaning, and drag reduction, facilitated by low surface energy. Aiming to understand the underlying interactions and forces, motivated numerous and detailed investigations of the static and dynamic wetting behavior of drops on PDMS-based surfaces. Here, we recognize the three most prevalent PDMS surface variants, namely liquid-infused (SLIPS/LIS), elastomeric, and liquid-like (SOCAL) surfaces. To understand, optimize, and tune the wetting properties of these PDMS surfaces, we review and compare their similarities and differences by discussing (i) the chemical and molecular structure, and (ii) the static and dynamic wetting behavior. We also provide (iii) an overview of methods and techniques to characterize PDMS-based surfaces and their wetting behavior. The static and dynamic wetting ridge is given particular attention, as it dominates energy dissipation, adhesion, and friction of sliding drops and influences the durability of the surfaces. We also discuss special features such as cloaking and wetting-induced phase separation. Key challenges and opportunities of these three surface variants are outlined.
Collapse
Affiliation(s)
- Lukas Hauer
- Institute for Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Physics at Interfaces, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Abhinav Naga
- Department of Physics, Durham University, DH1 3LE, UK
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FD, UK
| | - Rodrique G M Badr
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7-9, 55099 Mainz, Germany
| | - Jonathan T Pham
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, 45221 OH, USA
| | - William S Y Wong
- Department of Applied Physics, School of Science, Aalto University, 02150 Espoo, Finland
| | - Doris Vollmer
- Physics at Interfaces, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| |
Collapse
|
5
|
Raynard A, Abbas A, Armstrong S, Wells GG, McHale G, Sefiane K, Orejon D. Tuning contact line dynamics on slippery silicone oil grafted surfaces for sessile droplet evaporation. Sci Rep 2024; 14:1750. [PMID: 38242933 PMCID: PMC10799045 DOI: 10.1038/s41598-023-50579-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/21/2023] [Indexed: 01/21/2024] Open
Abstract
Controlling the dynamics of droplet evaporation is critical to numerous fundamental and industrial applications. The three main modes of evaporation so far reported on smooth surfaces are the constant contact radius (CCR), constant contact angle (CCA), and mixed mode. Previously reported methods for controlling droplet evaporation include chemical or physical modifications of the surfaces via surface coating. These often require complex multiple stage processing, which eventually enables similar droplet-surface interactions. By leveraging the change in the physicochemical properties of the outermost surface by different silicone oil grafting fabrication parameters, the evaporation dynamics and the duration of the different evaporation modes can be controlled. After grafting one layer of oil, the intrinsic hydrophilic silicon surface (contact angle (CA) ≈ 60°) is transformed into a hydrophobic surface (CA ≈ 108°) with low contact angle hysteresis (CAH). The CAH can be tuned between 1° and 20° depending on the fabrication parameters such as oil viscosity, volume, deposition method as well as the number of layers, which in turn control the duration of the different evaporation modes. In addition, the occurrence and strength of stick-slip behaviour during evaporation can be additionally controlled by the silicone oil grafting procedure adopted. These findings provide guidelines for controlling the droplet-surface interactions by either minimizing or maximising contact line initial pinning, stick-slip and/or constant contact angle modes of evaporation. We conclude that the simple and scalable silicone oil grafted coatings reported here provide similar functionalities to slippery liquid infused porous surfaces (SLIPSs), quasi-liquid surfaces (QLS), and/or slippery omniphobic covalently attached liquid (SOCAL) surfaces, by empowering pinning-free surfaces, and have great potential for use in self-cleaning surfaces or uniform particle deposition.
Collapse
Affiliation(s)
- Astrid Raynard
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, UK
| | - Anam Abbas
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, UK.
- Department of Mechanical Engineering, University of Engineering and Technology, Lahore, 39161, Pakistan.
| | - Steven Armstrong
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, UK
| | - Gary G Wells
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, UK
| | - Glen McHale
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, UK
| | - Khellil Sefiane
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, UK
| | - Daniel Orejon
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, UK.
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
| |
Collapse
|
6
|
Orejon D, Maeda Y, Zhang P, Lv F, Takata Y. Nanorough Is Not Slippery Enough: Implications on Shedding and Heat Transfer. ACS APPLIED MATERIALS & INTERFACES 2024; 16:1779-1793. [PMID: 38164911 PMCID: PMC10788867 DOI: 10.1021/acsami.3c14232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
Lowering droplet-surface interactions via the implementation of lubricant-infused surfaces (LISs) has received important attention in the past years. LISs offer enhanced droplet mobility with low sliding angles and the recently reported slippery Wenzel state, among others, empowered by the presence of the lubricant infused in between the structures, which eventually minimizes the direct interactions between liquid droplets and LISs. Current strategies to increase heat transfer during condensation phase-change relay on minimizing the thickness of the coating as well as enhancing condensate shedding. While further surface structuring may impose an additional heat transfer resistance, the presence of micro-structures eventually reduces the effective condensate-surface intimate interactions with the consequently decreased adhesion and enhanced shedding performance, which is investigated in this work. This is demonstrated by macroscopic and optical microscopy condensation experimental observations paying special attention at the liquid-lubricant and liquid-solid binary interactions at the droplet-LIS interface, which is further supported by a revisited force balance at the droplet triple contact line. Moreover, the occurrence of a condensation-coalescence-shedding regime is quantified for the first time with droplet growth rates one and two orders of magnitude greater than during condensation-coalescence and direct condensation regimes, respectively. Findings presented here are of great importance for the effective design and implementation of LISs via surface structure endowing accurate droplet mobility and control for applications such as anti-icing, self-cleaning, water harvesting, and/or liquid repellent surfaces as well as for condensation heat transfer.
Collapse
Affiliation(s)
- Daniel Orejon
- Institute
for Multiscale Thermofluids, School of Engineering, University of Edinburgh, Scotland EH9 3BF, United
Kingdom
- International
Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yota Maeda
- Department
of Mechanical Engineering, Thermofluid Physics Laboratory, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Peng Zhang
- Institute
of Refrigeration and Cryogenics, Shanghai
Jiao Tong University, Shanghai 200240, China
| | - Fengyong Lv
- School
of Urban Construction and Safety Engineering, Shanghai Institute of Technology, Shanghai 201418, China
| | - Yasuyuki Takata
- Institute
for Multiscale Thermofluids, School of Engineering, University of Edinburgh, Scotland EH9 3BF, United
Kingdom
- International
Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| |
Collapse
|
7
|
Kumar B, Upadhyay G, Bhardwaj R. Coupled Dynamics of Droplet Impact on a Flexible, Hydrophilic Cantilever Beam. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:18768-18783. [PMID: 38095945 DOI: 10.1021/acs.langmuir.3c02238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
We experimentally study the droplet impact on a flexible, hydrophilic cantilever beam. Droplets of water, water-glycerol (1:1 v/v), and glycerol were considered on a copper beam. Side visualization of the droplet impact on the cantilever was carried out by using a high-speed camera. We systematically vary cantilever stiffness to obtain a characteristic time scale of the beam dynamics, that is, shorter on the same order and longer than the characteristic time scale of droplet dynamics. Water droplet spreading reduces with an increase in the beam's flexibility, due to the "springboard effect". Results reveal that a threshold cantilever length exists beyond which the droplet vibration mode "locks-in" to the cantilever vibration mode. During lock-in, the bending energy of the beam increases with an increasing length or decreasing stiffness. The time-varying cantilever deflection exhibits an oscillatory, exponentially decaying response. However, in the case where both time scales are almost the same, we found a two-stage damping in the measurements: a fast, initial damping followed by a slower, damped response. We explain this damped response by the interplay of droplet and cantilever early dynamics. As expected, increasing the droplet viscosity dampens the magnitude of droplet spreading and displacement of the cantilever's tip due to a larger dissipation of kinetic energy in the bulk of the droplet. The decay is exponential in all cases, and the time taken to reduce the spreading and displacement is shorter with a larger viscosity. The damping coefficient is found to inversely scale with the cantilever length or mass. We corroborated the measurements with available analytical models, confirming the hypotheses used to explain the results. Overall, the present study provides fundamental insights into controlling the coupled dynamics of droplet and flexible substrates, with potential applications such as the design of efficient agricultural sprays and wings of microaerial vehicles.
Collapse
Affiliation(s)
- Bibek Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Gaurav Upadhyay
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Rajneesh Bhardwaj
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| |
Collapse
|
8
|
Celik N, Sahin F, Ruzi M, Ceylan A, Butt HJ, Onses MS. Mechanochemical Activation of Silicone for Large-Scale Fabrication of Anti-Biofouling Liquid-like Surfaces. ACS APPLIED MATERIALS & INTERFACES 2023; 15:54060-54072. [PMID: 37953492 DOI: 10.1021/acsami.3c11352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Large-scale preparation of liquid-like coatings with perfect transparency via solventless and room-temperature processes using low-cost and biocompatible materials is of tremendous interest for a broad range of applications. Here, we present a mechanochemical activation strategy for solventless grafting of poly(dimethylsiloxane) (PDMS) onto glass, silicon wafers, and ceramics. Activation is achieved via ball milling PDMS without using any solvents or additives prior to application. Ball milling results in chain scission and generation of free radicals, allowing room-temperature grafting at durations ≤1 h. The deposition of ball-milled PDMS can be facilitated by brushing or drop-casting, enabling large-scale applications. The resulting surfaces facilitate the sliding of droplets at angles <20° for liquids with surface tension ranging from 22 to 73 mN/m. An important application for public health is generating anti-biofouling coatings on sanitary ware. For example, PDMS-grafted surfaces prepared on a regular-size toilet bowl exhibit a 105-fold decrease in the attachment of bacteria from urine. These findings highlight the significant potential of mechanochemical processes for the practical preparation of liquid-like surfaces.
Collapse
Affiliation(s)
- Nusret Celik
- ERNAM─Erciyes University Nanotechnology Application and Research Center, 38039 Kayseri, Turkey
- Department of Materials Science and Engineering, Erciyes University, 38039 Kayseri, Turkey
| | - Furkan Sahin
- ERNAM─Erciyes University Nanotechnology Application and Research Center, 38039 Kayseri, Turkey
- Department of Biomedical Engineering, Faculty of Engineering and Architecture, Beykent University, 34398 Istanbul, Turkey
| | - Mahmut Ruzi
- ERNAM─Erciyes University Nanotechnology Application and Research Center, 38039 Kayseri, Turkey
| | - Ahmet Ceylan
- Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey
| | - Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, D-55128 Mainz, Germany
| | - Mustafa Serdar Onses
- ERNAM─Erciyes University Nanotechnology Application and Research Center, 38039 Kayseri, Turkey
- Department of Materials Science and Engineering, Erciyes University, 38039 Kayseri, Turkey
- UNAM-National Nanotechnology Research Center, Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| |
Collapse
|
9
|
Al-Mokhalelati K, Karabet F, Allaf A, Naddaf M, Assfour B, Al Lafi A. Silicone oils aided fabrication of paraffin wax coated super-hydrophobic sand: A spectroscopic study. Heliyon 2023; 9:e20874. [PMID: 37867885 PMCID: PMC10585292 DOI: 10.1016/j.heliyon.2023.e20874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 09/08/2023] [Accepted: 10/09/2023] [Indexed: 10/24/2023] Open
Abstract
To address the global alarm of desertification and boost plant progress in arid and desert environments, super-hydrophobic sand has been suggested and fabricated in numerous researches. In the present work, sand was hydrophobized by coating with a mixture of paraffin wax and silicone oils. The contact angle (CA) of sand with 4.5 w% silicone oils increased from 143.2° to 154.2° with decreasing the chain size of silicone oil, and the further addition of 13.5 w% of paraffin wax produced a super hydrophobic sand with a CA value up to 160° comparing to 154.2° without added paraffin wax. The Fourier Transform Infrared spectra suggested the development of inter molecular forces between silicone oil and sand as well as between paraffin and silicone oil, the driving force of which was the variation in viscosity of silicone oils. The later was higher in the case of lower molecular weight silicone oil. In particular, analyzing the characteristic bands of -(CH2)n-in paraffin wax, i.e. the corresponding bands at 720, 730, 1460 and 1470 cm-1 and the two bands at 1020 and 1095 cm-1 of silicone oil revealed that two roles of paraffin were taking place. While paraffin was placed between sand and silicone oil, it coated the sand particles when lower molecular weight silicone oil was used in the first procedures, whereas it coated the higher molecular weight silicone oil in the second procedures. Molecular dynamic calculation has been performed and confirmed the previous reached conclusions and showed that paraffin molecules were encapsulated in a silicone oil shell. The average adsorption energy of paraffin and silicon oil molecules on sand particles were 29.5 and 38.9 kcal mol-1 respectively.
Collapse
Affiliation(s)
- K. Al-Mokhalelati
- Department of Chemistry, Faculty of Science, Damascus University, Syrian Arab Republic
| | - F. Karabet
- Department of Chemistry, Faculty of Science, Damascus University, Syrian Arab Republic
| | - A.W. Allaf
- Department of Chemistry, Atomic Energy Commission, Damascus, P.O.Box 6091, Syrian Arab Republic
| | - M. Naddaf
- Department of Chemistry, Atomic Energy Commission, Damascus, P.O.Box 6091, Syrian Arab Republic
| | - B. Assfour
- Department of Chemistry, Atomic Energy Commission, Damascus, P.O.Box 6091, Syrian Arab Republic
| | - A.G. Al Lafi
- Department of Chemistry, Atomic Energy Commission, Damascus, P.O.Box 6091, Syrian Arab Republic
| |
Collapse
|