東華大學圖書館 |

Superhydrophobic Coatings: Topography and Composition Effects on the Corrosion Protection and Drag Reduction Behavior.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Superhydrophobic Coatings: Topography and Composition Effects on the Corrosion Protection and Drag Reduction Behavior./
Author:	Zheng, Keqin .
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2020,
Description:	108 p.
Notes:	Source: Dissertations Abstracts International, Volume: 81-09, Section: B.
Contained By:	Dissertations Abstracts International81-09B.
Subject:	Physical chemistry. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27668541
ISBN:	9781392564943

Superhydrophobic Coatings: Topography and Composition Effects on the Corrosion Protection and Drag Reduction Behavior.
Zheng, Keqin .

Superhydrophobic Coatings: Topography and Composition Effects on the Corrosion Protection and Drag Reduction Behavior. - Ann Arbor : ProQuest Dissertations & Theses, 2020 - 108 p.

Source: Dissertations Abstracts International, Volume: 81-09, Section: B.

Thesis (Ph.D.)--University of Massachusetts Lowell, 2020.

This item must not be sold to any third party vendors.

Superhydrophobicity, a special wetting phenomenon, has been widely studied for several decades since Barthlott discovered the lotus effect. This term is defined as a surface has large contact angle (> 150°) and very small sliding angle (< 10°) and allows water droplet to easily roll off the surface. In this work, as one of artificial surface, superhydrophobic composite coating is studied for practical applications in naval system such water-repellency, anti-corrosion and drag reduction to enhance the performance and reduce the downtime. A fundamental understanding between surface topography and performance has been achieved by correlating the topography, composite interface and properties for mentioned applications. In this dissertation, these correlations were depicted in following three chapters with experiment and result discussion.In the chapter 1, the study of the topography effect of superhydrophobic surfaces on the corrosion protection performance of steel is described through the air plastron behavior when subjected to an underwater environment. This work is using the spray coated superhydrophobic coating surface, composing of silica, epoxy and fluoroalkyl silane. The time-dependent behavior of air plastron that induced by superhydrophobic surface was observed and demonstrated that its local wetting transitions did not occur at the same time. A parallel corrosion test on regular superhydrophobic surface and wetted superhydrophobic surface demonstrated that the air plastron mentioned above postponed the corrosion to happen, in which the elongated protection time was equal to the lifetimeof air plastron. An experiment incorporating microscopy camera observation and surface topography characterization was conducted to correlate the topography and air plastron lifetime. It is found that the air plastron lifetime was demonstrated to be negatively related to the feature size.In the chapter 2, it focused on the effect of silica nanoparticle loading on the wetting behavior of a nanocomposite coating based on a novel organosilane binder. a series of nanocomposite coating with different silica content were fabricated. Due to the similar surface energy between binder and hydrophobic silica particles, the change in the wettability of different coatings can be attributed to the change in the topography. Experimental results supported by modeling demonstrated that a sharp change in contact angle hysteresis took place at a critical particle loading. Fluorescent dye staining was used to visualize the air-liquid interface evolution with particle loading, which explained the sharp transition of the receding angle. This technique also leads to a correlation between topography and this air-liquid-solid interface when coupled with the industrial confocal microscope. It indicates that in such droplet size condition, the spacing between 20-40 µm structures was crucial to achieve stable composite interface.In the chapter 3, the drag reduction behavior on the superhydrophobic coating is extensively studied in both short-term and long-term performance. The superhydrophobic coating samples with different particle loading were coated on the steel plate and subjected to rheological measurement. The short-term drag reduction performance was enhanced with more particle loaded and goes leveled eventually. The feature sizes and solid fractions extracted from their composite interfaces were in agreement with this change according to the theoretical modelling. The topography was correlated with drag reduction and future composite interface in a statistical way. It is found that both of them shows a reasonable dependency on the topography parameters, reduced peak height and autocorrelation length. At last, the long-term drag reduction was also investigated. Different from the high particle loading sample, this drag reduction on coating sample with 27.5% particle loading exhibits time-dependent characteristics, which was confirmed with the reason of sealed air plastron inside. A modelling was established by incorporating 2D diffusion of air, air plastron shrinkage and drag reduction, which successfully explained the observed exponential relationship between slip length and testing time. This long term drag reduction behavior suggests that the performance could be consistent if the boundary of composite interface is opened to the atmosphere.

ISBN: 9781392564943Subjects--Topical Terms:

1981412
Physical chemistry.
Subjects--Index Terms:

Composite coating

Superhydrophobic Coatings: Topography and Composition Effects on the Corrosion Protection and Drag Reduction Behavior.
LDR:05643nmm a2200385 4500 001 2275152
005 20201202130421.5
008 220723s2020 ||||||||||||||||| ||eng d
020 $a 9781392564943
035 $a (MiAaPQ)AAI27668541
035 $a AAI27668541
040 $a MiAaPQ $c MiAaPQ
100 1 $a Zheng, Keqin . $3 3553390
245 1 0 $a Superhydrophobic Coatings: Topography and Composition Effects on the Corrosion Protection and Drag Reduction Behavior.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2020
300 $a 108 p.
500 $a Source: Dissertations Abstracts International, Volume: 81-09, Section: B.
500 $a Advisor: Mead, Joey.
502 $a Thesis (Ph.D.)--University of Massachusetts Lowell, 2020.
506 $a This item must not be sold to any third party vendors.
520 $a Superhydrophobicity, a special wetting phenomenon, has been widely studied for several decades since Barthlott discovered the lotus effect. This term is defined as a surface has large contact angle (> 150°) and very small sliding angle (< 10°) and allows water droplet to easily roll off the surface. In this work, as one of artificial surface, superhydrophobic composite coating is studied for practical applications in naval system such water-repellency, anti-corrosion and drag reduction to enhance the performance and reduce the downtime. A fundamental understanding between surface topography and performance has been achieved by correlating the topography, composite interface and properties for mentioned applications. In this dissertation, these correlations were depicted in following three chapters with experiment and result discussion.In the chapter 1, the study of the topography effect of superhydrophobic surfaces on the corrosion protection performance of steel is described through the air plastron behavior when subjected to an underwater environment. This work is using the spray coated superhydrophobic coating surface, composing of silica, epoxy and fluoroalkyl silane. The time-dependent behavior of air plastron that induced by superhydrophobic surface was observed and demonstrated that its local wetting transitions did not occur at the same time. A parallel corrosion test on regular superhydrophobic surface and wetted superhydrophobic surface demonstrated that the air plastron mentioned above postponed the corrosion to happen, in which the elongated protection time was equal to the lifetimeof air plastron. An experiment incorporating microscopy camera observation and surface topography characterization was conducted to correlate the topography and air plastron lifetime. It is found that the air plastron lifetime was demonstrated to be negatively related to the feature size.In the chapter 2, it focused on the effect of silica nanoparticle loading on the wetting behavior of a nanocomposite coating based on a novel organosilane binder. a series of nanocomposite coating with different silica content were fabricated. Due to the similar surface energy between binder and hydrophobic silica particles, the change in the wettability of different coatings can be attributed to the change in the topography. Experimental results supported by modeling demonstrated that a sharp change in contact angle hysteresis took place at a critical particle loading. Fluorescent dye staining was used to visualize the air-liquid interface evolution with particle loading, which explained the sharp transition of the receding angle. This technique also leads to a correlation between topography and this air-liquid-solid interface when coupled with the industrial confocal microscope. It indicates that in such droplet size condition, the spacing between 20-40 µm structures was crucial to achieve stable composite interface.In the chapter 3, the drag reduction behavior on the superhydrophobic coating is extensively studied in both short-term and long-term performance. The superhydrophobic coating samples with different particle loading were coated on the steel plate and subjected to rheological measurement. The short-term drag reduction performance was enhanced with more particle loaded and goes leveled eventually. The feature sizes and solid fractions extracted from their composite interfaces were in agreement with this change according to the theoretical modelling. The topography was correlated with drag reduction and future composite interface in a statistical way. It is found that both of them shows a reasonable dependency on the topography parameters, reduced peak height and autocorrelation length. At last, the long-term drag reduction was also investigated. Different from the high particle loading sample, this drag reduction on coating sample with 27.5% particle loading exhibits time-dependent characteristics, which was confirmed with the reason of sealed air plastron inside. A modelling was established by incorporating 2D diffusion of air, air plastron shrinkage and drag reduction, which successfully explained the observed exponential relationship between slip length and testing time. This long term drag reduction behavior suggests that the performance could be consistent if the boundary of composite interface is opened to the atmosphere.
590 $a School code: 0111.
650 4 $a Physical chemistry. $3 1981412
650 4 $a Chemical engineering. $3 560457
650 4 $a Materials science. $3 543314
653 $a Composite coating
653 $a Composite interface
653 $a Corrosion protection
653 $a Drag reduction
653 $a Superhydrophobic
653 $a Wettability
690 $a 0794
690 $a 0494
690 $a 0542
710 2 $a University of Massachusetts Lowell. $b Plastics Engineering. $3 3550731
773 0 $t Dissertations Abstracts International $g 81-09B.
790 $a 0111
791 $a Ph.D.
792 $a 2020
793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27668541