ABSTRACTS

The following is a list of the abstracts for papers which will be presented in the THIRD INTERNATIONAL SYMPOSIUM ON ADHESION ASPECTS OF THIN FILMS(INCLUDING ADHESION MEASUREMENT AND METALLIZED PLASTICS). The listing is alphabetical by presenting author. This list is updated continually to add abstracts as they become available and make appropriate corrections. This list may be conveniently searched by using the editor provided with most popular browsers (e.g. Microsoft Explorer, Netscape, ... etc.)

1) Chemistry, Center for Materials Science and Engineering, School of

Physical Sciences, Rochester Institute of Technology, Rochester, NY

14623, USA

2) Qimonda North America, Richmond, VA 23150, USA

3) Xerox Corporation, Webster, NY 14580, USA

4) Physics, School of Physical Sciences, RIT, Rochester, NY 14623, USA

Modification of Fluoropolymer Surfaces to Contain Copper Fluoride: Relevance to Adhesion

Films of sputtered Cu were deposited on the surfaces of the fluoropolymers poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) and poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) and studied by angle-resolved XPS at take-off angles of 10*, 45* and 80*. PFA and FEP show enhanced interaction with sputtered Cu to produce fluoride ions relative to the more polycrystalline PTFE. At intermediate depths (45°), PFA and FEP exhibit the strongest fluoride F 1s signals compared to the fluoropolymer peaks. Argon ion etching of thin films of sputtered Cu on the fluoropolymers shows higher fluoride to fluoropolymer ratios than for thin films of evaporated Cu. The amount of fluoride ion detected reaches amaximum after brief Ar ion etching and then decreases with prolonged etching. Compared to untreated fluoropolymers, improved adhesion of evaporated Cu was observed on the fluoropolymer surfaces that were argon ion etched to expose fluoride ions.

Recent Advances in the Theory and Measurement of Thin Film Stress

(Abstract not yet available)

1) Kazakh British Technical University, 55 Tolebi Avenue, 050000, Almaty, KAZAKHSTAN

2) Institute of Chemical Sciences, 106 Walikhanov Street, 050010, Almaty, KAZAKHSTAN

A New Heat-resistant Alicyclic Polyimide on the Basis of Simple Oil-Refined Hydrocarbons

Hydrocarbon composition of oils of the range of Kazakhstan oilfields serve as an evidence of crude oil aromaticity and significant polycycloaromatic as well as naphthenes content, substituted benzenes, for example trimethylbenzene, tetramethylbenzene etc. Moreover, substituted naphthalenes are also to be found in fair quantities, di - and trimethylnaphthalenes particularly. Indicated aromatic and polycycloaromatic hydrocarbons serve as a perspective source of raw materials, which is required for the development of monomer production for the industrial organic synthesis.

Among the wide range of monomers for heterocyclic polymers synthesis dianhydrides of alicyclic tetracarboxylic acids are of interest, because of their accessibility from raw materials source such as benzene and its derivatives. Thus, dianhydrides of tricyclodecenetetracarboxylic acids can be obtained in mild conditions by the photochemical cycloaddition of maleic anhydride and its derivatives to different aromatic or heterocyclic hydrocarbons. Heterocyclochained polymers on the basis of these dianhydrides yield to entirely aromatics in heat resistance slightly enough and can compete with them in simplicity of monomers synthesis and accessibility of raw materials source.

Two new monomers such as dianhydrides of tricyclo-(4,2,2,0^2,5)-dec-7-ene-3,4,9,10-tetracarboxylic acid (DA) and 7-methyltricyclo-(4,2,2,0^2,5)-dec-7-ene-3,4,9,10-tetracarboxylic acid were prepared using common oil refined products maleic anhydride via either benzene or toluene. The monomers were used for the further synthesis of respective polyimide through their polycondensation with ODA confirmed by FTIR, proton NMR, TGA/SDTA and DSC data. Mechanical performances of the produced PI films possess appropriate values typical for aromatic PI, namely based on dianhydride of pyromellitic acid, while cost price of DA (MDA) polymers remarkably less.

Nano-scale Solid-interface Strength Measured by Hybrid Method of Nano-testing and Finite Element Analysis

(abstract not yet available)

1) RHESCA Co. Ltd., 15-17, Hino-Honmachi 1 Chome, 191-0011, JAPAN

2) Seikei University, 3-3-1 Kichijoji-kitamachi Musashino-shi Tokyo 180-8633, JAPAN

Application of FFT-based Signal Analysis to Micro-Scratch Testing for

Adhesion Strength Measurement of Thin Films and Measured Results Based on Different Measuring Parameters

The micro-scratch testing has been used to study the adhesion strength of thin films of 1 micron thick or less. A micro-scratch tester scratches a specimen with a horizontally vibrating diamond stylus to obtain signals originating from the fracture of the specimen. The diamond stylus is mounted at the tip of a cantilever of an audio cartridge, which can output signals for evaluating the occurrence of fractures and the critical load of coating films.

The micro-scratch tester picks-up not only the fracture signals but also vibration-related noise that is added to the output signals from the cantilever. To reduce this adverse effect of the noise, Baba, et al. applied the Fourier Transform to the output signals, thus successfully improving the S/N ratio of the signals.

In this report, a similar technology was used to re-evaluate whether or not the FFT approach is practical. First, the actual output signals from the micro-scratch tester were recorded, which were then converted into digital signals. Then, the approach based on the Fourier Transform was accurately followed for confirmation purposes. Second, the technique was modified in an attempt for further improvements. Finally this approach was evaluated by implementing it into our micro-scratch tester.

Coating films of dichroic mirrors, DLC-coatings on SUS substrates, and other metal coatings (titanium oxide, chromium, and aluminum) were tested with different measuring parameters in terms of thickness of films, radius of stylus, driving frequency, etc. to evaluate the performance of the micro-scratch testing with our approach. Experimental results showed that the approach was very practical and that the micro-scratch testing can surely contribute to studying the adhesion strength of thin films.

(e-mail: A.Fedorov@rug.nl )

Degradation of Adhesion in Deformed Polymer-metal Interfaces Studied by Laser Induced Delamination Technique

Adhesion properties of polymer coatings on metals subjected to deformations during manufacturing process are of great interest to modern industrial applications, including automotive industry and packaging of food. In this work, the effect of plastic deformations of metal substrate on the adhesion properties of polymer-metal interface is investigated. Steel samples laminated with polyethylene terephthalate (PET) were subjected to uniaxial tensile deformations which in some cases were followed by a thermal treatment. The experimental method used in this study is a laser induced delamination technique [1]. Particular interest was focused on the effect on adhesion of in-plane stress fields introduced in the coating by the deformation. Under certain conditions, such stresses can lead to a spontaneous delamination. In the experiments performed, both the practical work of adhesion and the in-plane stresses present in the coating were measured. The measurements have demonstrated degradation of adhesion of the metal-polymer interface as the deformation of the substrate increases. In line with expectations, the in-plane stresses introduced in the coating increased with the deformation. After annealing of the samples partial restoration of the adhesion was observed.

1. A. Fedorov, J.T.M. De Hosson, J. Appl. Physics 97, 123510 (2005)

A new Concept of Adhesion Promotion in Metal-Polymer Composites by Introduction of Covalently Bonded Hydrophobic Spacers at Interface

Several adhesion problems between metal layers and polymers exist in various electronic assemblies or other types of metal-polymer composites due to the deficiency or absence of covalent bonds associated with the strongly different thermal expansion coefficients of the materials or humidity migration along the interface. Here, the introduction of covalent bonds (i) into the interfaces bonded by spacer molecules (ii) of different chain length, stiffness and end groups, which are additionally equipped with hydrophobic functional groups (iii). The spacer molecules shall balance mechanical stress along the interface by its covalent bonding to the polymer and the metal as well and their flexible reaction on stress. Moreover, the use of hydrophobic spacer molecules are also able to avoid the migration of humidity to the interface and, therefore, to hinder hydrolysis of covalent bonds.

New Plasma Techniques for Polymer Surface Modification with Monotype Functional Groups

The most important problem of plasma exposure to polymers is the excess of energy delivered from the plasma. For attaching plasma atoms or fragments as (plasma gas-specific) functional groups only a few energy is necessary for replacing of a hydrogen atom by a functional group. The broad electron energy distribution and particularly the high-energy tail positioned at energies far in excess of chemical binding energies lead also to unspecific scissions of polymer backbones. Thus, plasma processing with polymers is often characterized by insufficient selectivity, irregular, randomly structured and exotic products of high-energy chemistry. Different strategies are developed to overcome this disadvantage. New and more selective processes were developed to produce the aspired monotype-functionalized polymer surface, (i) combination with post-plasma chemical processes applied for repairing the defect-rich structures and limiting the number of products if starting from the broad variety of produced products, (ii) using special plasma processes of high selectivity, (iii) using of the electrospray ionization deposition of intact macromolecules as ultra-thin film, (iv) application of pressure-pulsed plasmas to enhance the chemical polymer formation, (v) combination of plasma and electrochemistry by using underwater plasmas for polymer surface modifications. All these processes are introduced to produce a monotype (monosort) functional groups containing polymer surface which is necessary as anchoring point for further chemical grafting of spacers, molecules, proteins etc.

1) SIMAP INP Grenoble, FRANCE

2) LPM INSA Lyon, FRANCE

3) LITEN CEA, Grenoble FRANCE

Cracking and Deadhesion of Thin Metal Films on Mechanically Modified Polymer Surfaces

The cracking and deadhesion of thin metal films deposited on polymers is analysed from the results obtained by in-situ tensile experiments. The critical parameters (stress, strain) launching the above mentioned damage mechanisms are strongly dependent on the polymer substrate surface modification prior to the thin film deposition. As a matter of fact the substrate surfaces were mechanically grinded at different levels. From the results and observations which were obtained from in-situ tensile tests, cracking with or without debonding is discussed in relation to the redistribution of the stresses in the film during the damage process.

Adhesion and Mechanical Properties of Poly(tetrafluoroethylene) Poly(vinyl Alcohol) Composite Thin Films Prepared by Spin Coat Method

Poly(tetrafluoroethylene) (PTFE) and poly(vinyl alcohol) (PVA) and their composite thin films coated onto the nickel-titanium substrate by a spin coating were characterized. Relationship between the sintering temperature and mechanical properties, such as adhesion strength and shearing force, was evaluated. The adhesion strength of the PTFE-PVA composite and PVA thin films decreased with increase of the sintering temperature. Although shearing force of the PTFE thin film increased with increase of the sintering temperature, those of the PTFE-PVA composite and PVA thin films decreased. The adhesion strength between these PTFE thin films and nickel-titanium substrate were improved due to introduction of PVA interfacial layer [1]. In addition, friction coefficients of the spin coated thin films decreased with increase of the PTFE concentration [1].

Reference

[1] S.Iwamori and M.Mizoguchi, Materials Science and Technology, 43, 99(2006)

Industrialization and New Applications in Ion Assisted Reaction

(Abstract not yet available)

Polymer Functionalization and Thin Film Deposition by Cold Remote Nitrogen Plasma Process

Modifications of polymers surface assisted by cold plasma processes are receiving a growing interest. Especially, the use of plasma gases such as N2, O2 or air, cheap and environmentally safe are very attracting from an industrial point of view. Lifetime of atomic oxygen being very short, it is very difficult to operate with air or oxygen plasma as soon as a large volume plasma extension is required. But, it is possible to obtain cold remote nitrogen plasma reaching several m³ thanks to the long lifetime of atomic nitrogen explained by a redissociation mechanism. Moreover, a temperature around the ambient makes this plasma very attractive for functionalization and/or coating of polymers surface. Several applications of this plasma process are presented in this paper. The incorporation of new chemical functions during the treatment of polymer leads to an increase of their surface adhesion properties which has been turned to account for various industrial applications (painting, sticking, foaming and thermo-covering). The ability of this remote plasma to decompose, to polymerize or to react with a volatile chemical component is described through three examples involving polymer substrates: i) the deposition of metallic films; ii) the synthesis of a nitride film combining hardness and elastic behavior; iii) the elaboration of an organosilicon film showing interesting barrier properties. Adhesion aspects are investigated for all these examples.

Biofouling-resistant Materials for Medical Applications

A major concern in the treatment of hospitalized or chronically ill individuals is medical device infection. For example, infection of catheters is especially troublesome, because these infections may quickly progress from the device site to involve other organs (e.g., endocarditis) or the entire body (e.g., septicemia). There is considerable risk of bacteria and endotoxin discharge from bacteria, algae, and/or fungi biofilms, which serve as reservoirs for continuous contamination. The physical, chemical and biological properties of several biofouling-resistant materials, including diamondlike carbon-silver-platinum thin films, nanocrystalline diamond thin films, carbon nanotube composite films, and 3,4-dihydroxyphenyl-Opthamology-alanine-modified poly(ethylene glycol) films, will be discussed. In addition, the use of biofouling-resistant materials on the surfaces of catheters and other medical devices will be described.

1) School of Materials Science and Engineering, Andong National University, KOREA

2) Central R&D Institute, Samsung Electro-mechanics, Suwon, KOREA

3) Surface Technology Research Center, Korea Institute of Machinery and Materials, Changwon, KOREA

*ybpark@andong.ac.kr <Corresponding Author>

Interfacial Adhesion of Inkjet-Printed Ag on Flexible Polyimide Substrate

Inkjet printing technology is a direct writing technique for fabrication of the electronic circuits on the glass or the flexible substrates. Even though there are many advantages including low cost, low temperature process, solution processing, and rapid prototyping, the interfacial adhesion between inkjet printed Ag film and flexible polymer substrate is known to be very poor, which can be interfacial reliability issues for flexible electronics applications. In this work, the effect of CF₄ plasma treatment conditions of polyimide surface on the interfacial adhesion energy are evaluated from 180o peel test for various annealing and temperature/humidity conditions. Extensive surface analysis using AES, XPS, and AFM is performed to understand the fundamental adhesion enhancement mechanism due to CF₄ plasma treatment. Unique adhesion results during 85 C/85%R.H. temperature/humidity conditions are also discussed in detail.

A New Method of Obtaining Epoxy Waterproof Coatings

We have studied the new method of obtaining protective waterproof coatings on the basis of epoxy oligomers in the systems preventing corrosion of engineering and hydrotechnical equipment, port buildings, sea technics, maintained on the open air and undergoing temperature waving, constant or periodical impact of moisture and water. Existing method of obtaining protective waterproof coatings by the means of laying on polyethylenepolyamine as a hardener of epoxy oligomers and benzyl alcohol as a modifier on the metallic substrate leads to insufficient adhesion durability. Usage of epoxidised diene polymer doesn't provide reproducible results and adequate water resistance. Excess of water absorption, insufficient adhesion and water resistance of formed protective coat are limiting the usage of ready-witted epoxy enamels with epoxy hardeners. We have found that the formation of grounding coat on the metallic substrate using oligoaminephenylene before laying on epoxy enamels with hardeners sufficiently increases water resistance. It can be explained by the presence of linked aromatic rings and -NH₂ groups, which provide the increment of adhesionally active groups in the area of epoxy oligomer coat-metal contact and also leads to deepened sewing with formation of netting polymer structure, known to be less penetrable for the molecules of water.

Grain Boundary Induced Stresses in Polycrystalline Coatings and Thin Films

(Abstract not yet available)

Department of Applied Physics, Netherlands Institute of Metals Research, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, THE NETHERLANDS; w.p.vellinga@rug.nl

Residual stress and delamination front geometry on polymer-metal interfaces

This paper addresses the adhesion between polymers and metals in general, and specifically the influence of residual stresses and roughness on delamination mechanisms. The geometry of delamination fronts between PETG and a Cr coating on a glass substrate were studied using in-situ optical polarisation microscopy in an asymmetric double cantilever beam geometry. The geometry of a delamination front along the polymer-metal interface was found to be correlated with the residual stress state due to the thermal history of the samples. Specifically, it appeared that parts of a polymer-metal interface that are subjected to compressive residual stresses acting normal to the interface have a slightly higher effective local energy release rate. Moreover it is shown that after ageing under loading at such locations a delamination front is more likely to propagate into the polymer, causing a much higher peak energy release rate. The observations suggest that the geometry of polymer coatings may be optimised to stabilize them against delamination.

1) Hahn-Schickard-Institute of Microassembly Technology HSG-IMAT, Stuttgart, GERMANY

2) University of Stuttgart, Institute of Micro and Precision Engineering,

GERMANY

A New Device for Testing the Adhesion of Conductors on Polymers

Miniaturisation and 3D capability of moulded interconnect devices (MID) offer great opportunities for various applications in a broad industrial field. The adhesion or adhesive strength, respectively, of the conductors on the polymer substrates thereby is an essential quality feature of the MID part. Standard methods like peel and pull test are not suitable to characterise the adhesion particularly when the width of the conductors is only a several hundred microns and the thickness less than 20 µm. To overcome the disadvantage of the known test methods, a new measuring device for determining the adhesion has been developed and built up at HSG-IMAT. The measuring principle of the device utilises a micro chisel and force sensors to peel the conductor off the polymer substrate and measure the required forces at the same time. The force that is needed to peel off the conductor is understood to be connected to the adhesive strength. First measurements on different polymer substrates showed repeatable and promising results. Within this paper first results on measurements of the adhesive strength that have been obtained by using the new device will be presented.