The use of nano-/microlayers, self-healing and slow-release coatings to prevent corrosion and biofouling

Abstract

The mitigation of corrosion and biofouling is a challenge. Through application of chemicals and special techniques can slow these undesired processes, an effective resolution requires a multidisciplinary approach involving scientists, engineers, and metallurgists. In order to understand the importance of the use of nano-and microlayers as well as selfhealing coatings, the basic concepts of corrosion, corrosion mechanisms, corrosion inhibition and the microbiologically influenced corrosion will be summarised. The preparation, characterization and application of Langmuir-Blodgett and self assembled nanolayers in corrosive and microbial environment will be discussed. Preparation and characterization of microcapsules/ microspheres and their application in coatings will be demonstrated by a number of examples.Keywords: nano-and microcoating, self-healing, slow-release, anticorrosion, antifouling IntroductionCorrosion is a well-known problem all over the world. It consumes a significant part of the gross national product (GDP) of developed and developing countries. A number of authors have provided comprehensive introductions to corrosion mainly in aqueous and wet environments (Jones, 1991;Kaesche, 2003; McCafferety, 2010). Corrosion is the destructive result of the chemical/electrochemical reactions between metals and the environment. Corrosive reactions involve water in either liquid or condensed phases. Most corrosion reactions are electrochemical processes. These involve electron or charge transfer in aqueous solution which leads to metal dissolution (anodic reaction). Depending on the pH of the solution, either hydrogen or hydroxonium ions evolve, resulting in oxides, oxyhydroxides, hydroxides and salts formed on the metal surface (cathodic reaction). The electrochemical potential or electron activity affects the rate of corrosion reaction. To understand corrosion it is necessary to discuss briefly the types of corrosion and the reactions involved.Corrosion occurs in various forms.-Uniform corrosion: The metal surface must be compositionally uniform; the aggressive environment has the same access to all parts of the metal. This type of

Polystyrene films as barrier layers for corrosion protection of copper and copper alloys

“…Nanocoatings offer a new alternative solution of equal or better efficiency, being more cost-effective and implying less environmental load [4]. Self-assembled monolayers (SAM), Langmuir-Blodgett (LB) films and other organic thin films with the thickness of a few nanometres have been investigated and used for a long time in corrosion protection and against biofouling.…”

A comparison of contact angle measurement results obtained on bare, treated, and coated alloy samples by both dynamic sessile drop and Wilhelmy method

“…These tubes suffer from biofouling and the consecutive microbially-induced corrosion [14]. Nanolayers are potential solutions for the mitigation of the problem [15][16][17][18][19][20][21][22], and the success of the nanolayer coating procedure is routinely checked by CA measurements [23].…”

Micro/nanocapsules for anticorrosion coatings

“…The reaction parameters will determine the thickness, hardness of the shell wall (Szabó et al, 2011;Telegdi et al, 2014). One must keep in mind that a too thin shell will be destroyed already during the storage or during the application of the paint.…”

“…Matrix type particles employed in an aqueous environment with specified parameters, such as temperature, pH, and ionic strength, possess certain amount of water depending on their structure which allows continuous leaching of the active agents through diffusion (Telegdi et al, 2014, Mittal, V., 2014.…”

“…Inhibiting agents discharge rates from microcapsules and solid spheres tend to decrease with time however the amalgamation of encapsulated and free substances in the paint may lead to an equilibrated flux of the active agent (Telegdi et al, 2014). Nano-container is one of the main approaches for self-healing coatings applied for loading of active inhibiting agents with shell possessing controlled permeability specific to several triggers (Grigoriev et al, 2017).…”