Superhydrophobic Polymer Coatings

Fundamentals, Design, Fabrication, and Applications

Sushanta Samal, Smita Mohanty, Sanjay Kumar Nayak

• Publisher: Elsevier
• Year: 2019
• Print ISBN: 9780128166710
• eBook ISBN: 9780128172834
• Topic: Technology & Engineering
• Subtopic: Engineering General
• Index: Technology & Engineering

Superhydrophobic Polymer Coatings: Fundamentals, Design, Fabrication, and Applications offers a comprehensive overview of the preparation and applications of polymer coatings with superhydrophobicity, guiding the reader through advanced techniques and scientific principles. Sections present detailed information on the fundamental theories and methods behind the preparation of superhydrophobic polymer coatings and demonstrate the current and potential applications of these materials, covering a range of novel and marketable uses across industry, including coatings with properties such as foul resistance and self-cleaning, anti-icing and ice-release, corrosion inhibition, antibacterial, anti-reflection, slip and drag reduction, oil-water separation, and advanced medical applications.This book is a highly valuable resource for academic researchers, scientists and advanced students working on polymer coatings or polymer surface modifications, as well as professionals across polymer science, polymer chemistry, plastics engineering, and materials science. The detailed information in this book will also be of great interest to scientists, R&D professionals, product designers and engineers who are looking to develop products with superhydrophobic coatings.- Presents in-depth information on the advanced methods required in the preparation of superhydrophobic polymer coatings- Covers the latest advances in the design of polymer coatings with superhydrophobic properties, including nanofabrication- Explains cutting-edge industrial and medical applications, including self-cleaning coatings, corrosion inhibition, anti-icing and ice-release, and oil-water separation

Section II

Potential applications of superhydrophobic polymer coatings

Chapter 8

Superhydrophobic foul resistant and self-cleaning polymer coating

Mohamed S. Selim^a,b; Sherif A. El-Safty^a,c; Mohamed A. Shenashen^{a,b a} National Institute for Materials Science (NIMS), Tsukubashi, Japan
^b Petroleum Application Department, Egyptian Petroleum Research Institute (EPRI), Nasr City, Egypt
^c Faculty of Engineering and Advanced Manufacturing, University of Sunderland, Sunderland, United Kingdom

Abstract

Since the prohibition of using organo-tin compounds in marine antifouling paints in 2003, global interest was directed toward ecofriendly alternatives, particularly silicone-based fouling-release coatings. This technology hinders fouling settling because of an extreme antiadhesion and self-cleaning mechanism. Natural superhydrophobic surfaces are being researched to develop novel self-cleaning nanostructured coating materials given their promising fouling-release characteristics. Superhydrophobic fouling-release surfaces with minimum surface free energy are promising candidates for the shipping industry. Many feasible superhydrophobic self-cleaning nanocomposite coatings rather than biocidal solutions have been developed to counter biofouling. Various inorganic nanofillers are dispersed in the polymeric material and applied to increase superhydrophobicity and fouling, thereby providing a chemically inert surface that prevents the fouling of organisms. This chapter describes the behavior of superhydrophobic self-cleaning coatings and the effects of their surface free energy and roughness on fouling antiadhesion performance. Recent advancements in superhydrophobic nanocomposite coatings for the fouling resistance of marine ship hulls are discussed. Subtle structural changes in the reported fouling-release nanocomposite coatings provide outstanding self-cleaning surfaces. The chapter ends with an account of current and future developments, such as superhydrophobic graphene-based nanocoatings and ternary nanocomposite surfaces.

Keywords

Ecofriendly; Fouling release; Superhydrophobic surfaces; Self-cleaning; Nanocomposite; Graphene

1 Introduction

Biofouling is caused by abiotic and biotic dissolved materials, animals, and plants in seawater and negatively affects immersed man-made structures [1, 2]. It causes severe ecological and economic problems for the shipping industry with nearly US$150 billion annual cost in transportation. Fouling adhesion to the hull increases the ship's frictional resistance and hydrodynamic weight and reduces its velocity [2, 3]. This phenomenon results in elevated consumption of fuel and emissions of deleterious gases to the atmosphere [4]. Much emphasis is given on the fouling prevention of ship hulls [5]. The increased global embargo and restrictions associated with the application of biocide-containing antifouling coatings resulted in the development of ecofriendly alternatives [6]. Nonstick fouling release (FR) nanocoatings represent moving targets with conformationally mobile surfaces that prevent the adhesion of fouling species. FR coating technology, including silicone compounds and fluoropolymers, prevents fouling via a self-cleaning design [7]. Silicone polymers (especially polydimethylsiloxane (PDMS)) are more effective than fluoropolymers in FR coatings [8]. Fouling attachments are not facilely released because the stiff fluorine atoms cannot rotate about in the polymeric backbone linkages [9].

PDMS-based coatings provide nontoxic, hydrophobic, high molecular mobility, fouling repellence, and heat and oxidation resistance [8]. PDMS films exhibit high smoothness, hydrophobic character, structural mobility, reduced porosity, and free energy [10]. The FR attitude of PDMSs is improved by the distribution of inorganic nanoscale fillers [11]. This technique is cost efficient for marine durable coating applications [12]. Inorganic-organic surfaces can enhance the ability of self-cleaning and FR behavior of PDMS via designing superhydrophobic surfaces. These surfaces exhibit reduced surface free energy, increased contact angle (> 150 degrees), homogenous roughness, and minimized contact angle hysteresis (< 10 degrees), which afford FR terminology [13]. Self-cleaning surfaces can also introduce creative solutions for innovative FR paints [14]. Such nanocoated surface depends on chemical functionality and micro/nano binary structure of the nanocomposite coatings [15].

High superhydrophobicity and self-cleaning features were induced using metal oxide nanostructures and graphene-based materials as nanofillers in the FR nanocomposite coatings [16]. These trends introduce ecofriendly and durable alternatives to the commercial antifouling paints [17].

In this chapter, the main achievements in superhydrophobic FR and self-cleaning nanosurfaces are outlined. Environment-friendly coating techniques for fouling hindrance in the shipping industry are also demonstrated. The effects of various nanostructured materials on the efficiency of FR coatings were elicited. A comprehensive scientific approach to develop authentic green and cost-saving superhydrophobic self-cleaning nanocomposite solutions for marine antifouling problems was executed.

2 Marine biofouling

Marine biofouling is caused by various marine organisms, which can be sectioned based on their sizes, into biofilm, microfouling, and macrofouling [18, 19]. The gathering of microbial progenies on the extracellular polymeric substance material excreted by microorganisms is known as the biofilm [20, 21]. The cells of bacteria attach to the surface, divide to daughter cells, and grow and divide again [22]. Biofilm formation protects the microbial progenies against natural stresses, including osmotic shock, pH and temperature variations, desiccation, and biocides [23]. Biofilm is a complicated structure of aggregates, cells, and microbial progenies [24]. Adsorption of inorganic and organic macromolecules, such as protein and polysaccharides is the primary cause for biofilms [25, 26]. Microfouling can be divided into the following two categories [27]:

• - Primary colonization: primary colonizers, such as diatoms and bacteria, adsorb on the biofilm through physical adhesion forces. These strains can be facilely eliminated, and thus, this adsorption is reversible.
• - Secondary colonization: these colonizers, including protozoa and spores of macroalgae, are part of the microfilm [28, 29]. The mass of the microfilm increases nonlinearly.

Macrofouling, which can be soft or hard fouling, is of great research interest because it greatly affects the ship's drag resistance and hydrodynamic weight. Macrofouling is caused by organisms, such as animals and plants [30].

3 Fouling-related costs

Biofouling is a very costly problem, especially for the shipping industry. Billions of dollars are wasted every year because of fouling and their negative effects. More than 90% of the world trade is carried out by shipping, which represents the major facilitator for the global commerce. Fouling causes th...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Section I: Fundamental, design and fabrication of superhydrophobic polymer coatings
• Section II: Potential applications of superhydrophobic polymer coatings
• Index