Special Issue "Advances in Surface Coatings"

Guest Editor
Prof. Dr. Frank A. Müller
Institute of Materials Science and Technology (IMT), Friedrich-Schiller-University of Jena, Löbdergraben 32, D-07743 Jena, Germany
Website: http://www.matwi.uni-jena.de/start.html.en
E-Mail:
Interests: science and technology of surfaces and interfaces; surface modification and functionalization; coatings; biomaterials; biomimetic materials; nanoparticles

Dear Colleagues,

The physical, chemical and mechanical properties of a material surface determine its applicability in many technical devices. Numerous applications could not be realized without the use of surface modifications, coatings and thin film technology. Therefore, the need for efficient and effective methods of surface modification is becoming increasingly evident to allow the production of far superior products in terms of wear resistance, corrosion protection, enhanced biocompatibility, thermal insulation, improved optical and altered electronic properties. Coating technologies of particular interest include physical and chemical vapour deposition, thermal spraying, electrochemical deposition, sol-gel-syntheses, and plating. Surface modification includes directed energy techniques such as ion, electron and laser beams as well as etching procedures and thermo-chemical diffusion. Beyond that, monolayers (e.g. SAM, Langmuir-Blodgett) have attained high significance in preparing thin films to modify biomedical surfaces. Novel techniques to prepare patterned surfaces (e.g. nanoimprint lithography, microcontact printing) have proven their potential for the fabrication of integrated circuits and bioactive implants.

In this special issue novel trends related to surface engineering and coating technology for the production of functional materials surfaces will be highlighted. Particular emphasis will be placed on novel fabrication methods, materials and applications, new characterization techniques as well as numerical simulation and modeling.

Prof. Dr. Frank A. Müller
Guest Editor

Submission

All manuscripts should be submitted to materials@mdpi.org with a copy to the Guest Editor. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this Open Access journal is 800 CHF per accepted paper.

• properties and applications
• coating technologies
• surface modification
• thin films
• patterned surfaces
• biomimetic coatings
• functional gradient coatings
• mechanisms of adhesion
• interfaces
• numerical simulation / modeling
• characterization of coatings / thin films

Feature Paper:

Type of Paper: Article
Title: Theoretical Analysis of Formation of Two Zones Microstructure in Suspension Plasma Sprayed Coatings
Authors: Lech Pawlowski¹, Stefan Kozerski² and Leszek Latka¹
Affiliations: ¹ Service of Thermal Spraying at ENSCL, BP 90108, 59650 Villeneuve d’Ascq, France
² Department of Welding at Faculty of Mechanics, Wroclaw University of Technology, 50-371 Wroclaw, Poland
Abstract: Suspension plasma spraying is a process which enables production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected as continuous stream or atomized liquid into plasma jet and the liquid additives get evaporated. The remaining fine solids are molten and get agglomerated with other molten particles or remain solid depending on their trajectory in the plasma jet. The coating’s microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. In fact, the previous experimental studies [1,2] carried out for plasma sprayed hydroxyapatite coatings with use of continuous suspension injection, enabled to find out two zones microstructure which correspond to the groups of particles: (i) dense zone formed from well molten particles, and, (ii) sintered zone formed from fine solid particles arrived on the substrate in solid state. The present paper concentrates on the theoretical analysis of the process of formation of these two zones. A particular attention is paid to the description of the process of fine grains sintering. The experimental study has been carried out in order to establish the convective heat flux delivered by the plasma jet to the coatings at the depositions. The experimental data were used to establish a simple model of fine hydroxyapatite particles sintering. On the other hand, the mathematical description of deformation and solidification of molten hydroxyapatite particles was made. The results were compared with the experimentally observed microstructures.
References: [1] Kozerski, S.; Pawlowski, L.; Jaworski, R.; Roudet, F.; Petit, F. Two zones microstructure of suspension plasma sprayed hydroxyapatite coatings. Surf. Coat. Technol. 2009, doi:10.1016/j.surfcoat.2009.09.020
[2] Podlesak, H.; Pawlowski, L.; d’Haese, R.; Laureyns, J.; Lampke, T.; Bellayer, S. Advanced microstructural of suspension plasma sprayed hydroxapatite coatings, submitted for publication in J. Thermal Spray Technol.

Regular Paper:

Type of Paper: Review
Title: Imaging Analysis of Carbohydrate-Modified Surfaces Using ToF-SIMS and SPR
Authors: Kailey Bolles¹, Fang Cheng², Manish Dubey³ and Daniel Ratner²
Affiliations: ¹ Whitman College, 345 Boyer Ave., Walla Walla, WA 99362, Washington, USA
² Dept. of Bioengineering, University of Washington, Seattle, WA 99362, Washington, USA
³ NESAC/Bio, University of Washington, Seattle, WA 99362, Washington, USA; E-Mail: dratner@u.washington.edu
Abstract: Covalent modification of surfaces with carbohydrates is a prerequisite for a variety of glycomics-based biomedical applications, including functionalized biomaterials, glycoarrays, and glycan-based biosensors. The precise chemistry of glycan immobilization plays an essential role in the bioavailability and function of the bound carbohydrate moiety. However, there is a paucity of analytical methods to characterize carbohydrate-modified surfaces, making it difficult to address and optimize surface chemistries for specific applications. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a highly surface sensitive technique suited for probing molecular composition at the biomaterial interface. Expanding ToF-SIMS analysis to study carbohydrate-modified materials would increase our understanding of these new surface chemistries and advance the development of novel tools in the nascent field of glycomics. In this report, a glycan-modified surface was synthesized and characterized by ToF-SIMS imaging analysis. A multivariate technique based on principal components analysis (PCA) was used to analyze the SIMS data and obtain ToF-SIMS images of functionalized surfaces. These images reveal chemical species related to the immobilized glycan, underlying glycan-reactive chemistries and adventitious contaminants. Printed glycoarray elements (spots) were also interrogated to visualize spatial distribution and spot homogeneity of immobilized glycan. The biological function of the surface-bound glycan was validated using specific carbohydrate-binding proteins (lectins) as characterized by Surface Plasmon Resonance Imaging (SPRi). Our results demonstrate that ToF-SIMS combined with PCA is capable of assessing carbohydrate-modified surfaces and will play an essential role in optimizing biointerfacial chemistries of materials displaying immobilized carbohydrates.

Type of paper: Review
Tentative title : Zeolite coatings on structured supports: advances in preparation methods and catalytic processes for environmental applications.
Authors: Juan M. Zamaro and Eduardo E. Miró
Affiliation: Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe, Argentina; E-Mail: emiro@fiq.unl.edu.ar (E. E. M.)
Abstract: Interest in zeolitic materials for environmental applications has considerably increased in recent years, consequently spurring research in areas such as selective reduction of NOx, oxidation of volatile organic compounds and adsorption of hydrocarbons. Considering the usual conditions of high flows and the presence of particles in those processes, low pressure drop and good tolerance to plugging by dust are essential requisites leading to the use of catalytic monoliths. Zeolite monoliths can be obtained either under the form of extrudates in which the zeolitic material is used to manufacture the monolith, or by the deposition of the zeolite as a coating onto a structured substrate.
Zeolite coating layers can be made in two different ways: by hydrothermal synthesis (direct synthesis, seeded growth or vapor phase synthesis), and by the deposition from a slurry of zeolite particles followed by a stabilizing thermal treatment. Both methods will be discussed in this review. The first method has the advantage of a stronger adhesion of the coating to the support. The main disadvantages of this method, however, are that it is considerably more complex than slurry-coating and that a dense layer can be formed with small intercrystalline pores in which diffusion limitations can occur.
In this review, relevant literature will by critically discussed, and it will be enriched with the experience generated at the authors’own laboratories.

Type of Paper: Review
Title: Thin Film Deposition Using Energetic Ions
Authors: D. Manova and S. Mändl
Affiliation: Leibniz-Institut für Oberflächenmodifizierung, Permoserstr. 15, 04318 Leipzig, Germany; E-Mail: stephan.maendl@iom-leipzig.de
Abstract: One important recent trend in deposition technology is the continuous expansion of available processes towards higher ion assistance with the subsequent beneficial effects on film properties. Nowadays, a multitude of processes, including vacuum arc deposition, laser ablation and deposition, ion assisted deposition, high power impulse magnetron sputtering and plasma immersion ion implantation is available. However, obstacles to overcome are present in all technologies – but not all in one technology – including line-of-sight processes, particle contaminations, low growth rates, which lead to ongoing process refinements and development of new methods. Concerning the deposited thin films, control of energetic ion bombardment leads to improved adhesion, reduced substrate temperatures, adjustment of surface texture, phase formation and nanotopography, as well as control of intrinsic stress within the films. This review illustrates recent tendencies for both areas, plasma process and solid state surface processes.

Type of Paper: Review
Title: Use of Hydrophobins to Create Bio-Active Surfaces
Authors: Filippo Zampieri ^1,2,3, Karin Scholtmeijer ³ and Han A.B. Wösten ³
Affiliations: ¹BiOMaDe Technology Foundation, Nijenborgh 4, 9747 AG Groningen, The Netherlands
² Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology - Institute (GBB), University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands
³ Microbiology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands; E-Mails: F. Zampieri@uu.nl; K.Scholtmeijer@uu.nl; H.A.B.Wosten@uu.nl
Abstract: Small secreted proteins called hydrophobins play multiple roles in the life cycle of filamentous fungi. For example, they mediate the formation of aerial structures such as aerial hyphae, fruiting bodies and spores and allow attachment of hyphae to hydrophobic surfaces during fungal pathogenesis. Once secreted, hydrophobins self-assemble when they contact a hydrophobic-hydrophilic interface. As a result, an amphipathic surface active protein film is formed that changes the nature of the interface. Self-assembly at a hydrophobic surface results in increased wettability, whereas a hydrophilic surface turns hydrophobic. Differences in the solubility of the self-assembled protein films distinguish class I and class II hydrophobins. Class I assemblies are highly insoluble and can only be dissociated in agents such as trifluoroacetic acid or perfomic acid. In contrast, class II hydrophobins can be easily dissolved in detergents such as SDS or in 60% ethanol. Both classes can be used to change properties of hydrophilic-hydrophobic interfaces. Class II hydrophobins are preferred in applications such as protein purification where the hydrophobin should not assemble into a water-insoluble form. Class I hydrophobins are preferred when a stable protein film is required. Such a film is essential to increase biocompatibility of medical implants and to immobilize enzymes for biosensor surfaces. In this review we will discuss structure and self-assembly of hydrophobins and the use of these proteins in medical and technical applications.
Keywords: hydrophobin; self-assembly; wettability; coating of surfaces; immobilization