DOCSLIB.ORG

Surface Modification of Polytetrafluoroethylene (PTFE) with Vacuum UV Radiation from Helium Microwave Plasma to Enhance the Adhesion of Sputtered Copper Xiaolu Liao

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Surface Modification of Polytetrafluoroethylene (PTFE) with Vacuum UV Radiation from Helium Microwave Plasma to Enhance the Adhesion of Sputtered Copper Xiaolu Liao Rochester Institute of Technology RIT Scholar Works Theses Thesis/Dissertation Collections 2004 Surface modification of polytetrafluoroethylene (PTFE) with Vacuum UV radiation from helium microwave plasma to enhance the adhesion of sputtered copper Xiaolu Liao Follow this and additional works at: http://scholarworks.rit.edu/theses Recommended Citation Liao, Xiaolu, "Surface modification of polytetrafluoroethylene (PTFE) with Vacuum UV radiation from helium microwave plasma to enhance the adhesion of sputtered copper" (2004). Thesis. Rochester Institute of Technology. Accessed from This Thesis is brought to you for free and open access by the Thesis/Dissertation Collections at RIT Scholar Works. It has been accepted for inclusion in Theses by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. SURFACE MODIFICATION OF POLYTETRAFLUOROETHYLENE (PTFE) WITH VACUUM UV RADIATION FROM HELIUM MICROWAVE PLASMA TO ENHANCE THE ADHESION OF SPUTTERED COPPER Xiaolu Liao Thesis SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF CHEMISTRY ROCHESTER INSTITUTE OF THE TECHNOLOGY ROCHESTER, NEW YORK March, 2004 SURFACE MODIFICATION OF POL YTETRAFLUOROETHYLENE (PTFE) WITH VACUUM UV RADIATION FROM HELIUM MICROWAVE PLASMA TO ENHANCE THE ADHESION OF SPUTIERED COPPER XIAOLU LlAO March,2004 Approved: Gerald A. Takacs Thesis Advisor T. C. Morrill Department Head COPYRIGHT STATEMENT Title of Thesis: SURFACE MODIFICATION OF POLYTETRAFLUOROETHYLENE (PTFE) WITH VACUUM UV RADIATION FROM HELIUM MICROWAVE PLASMA TO ENHANCE THE ADHESION OF SPUTTERED COPPER I, Xiaolu Liao, hereby grants permission to the Wallace Memorial Library, of Rochester Institute of Technology, to reproduce my thesis in whole or in part. Any reproduction will not be for commercial use or profit. in ACKNOWLEDGEMENTS I would like to thank Dr. Gerald A. Takacs for his guidance and kind support. I would like to thank my committee members (Dr. Gerald A. Takacs, Dr. Alan B. Entenberg, Dr. Massoud J. Miri, Dr. John P. Neenan) and the chemistry department for their great support. I would like to thank Dr. Entenberg of the Physics Department, RIT, for the copper deposition and instruction on the peel test and vacuum system, Dr. Kahn of the School of Photographic Arts & Science, RIT, for the use of the SEM instrument, and Mr. F. D. Egitto, and Dr. L. J. Matienzo, of Endicott Interconnect Technologies, Inc. for the XPS analysis. I appreciate the outstanding people that I worked with in the RIT Plasma Lab. They are: Zheng Sun, Hrishikesh Desai, Uger Sener and Wagner Dasilva. To my mother and my father: Thanks for the love, understanding and support you have given me. IV Table of Contents 1. INTRODUCTION 1 2. EXPERIMENTAL 10 2.1 Downstream Microwave Plasma System 10 2.1.1 Reactor Chamber and Quartz/Glass Injector Tube 11 2.1.2 Pressure Gauge 13 2.1.3 Mass Flow Controller And Gas Flow Readout Unit 13 2.1.4 Microwave Discharge 14 2.1.5 Vacuum System 14 2.1. 6 Spark Coil/ Tesla Coil 15 2.2 Surface Analysis 16 2.2.1 X-ray Photoelectron Spectroscopy 16 2.2.2 Scanning Electron Microscopy 16 2.2.3 Contact Angle Measurement 17 2.2.4 Weight Loss 19 2.3 Copper Deposition And Scotch Tape Test 19 2.3.1 Copper Deposition 19 2.3.2 Scotch Tape Test 21 2.4 Sample Preparation 22 3. RESULTS 23 3.1 Contact Angle Measurement 23 3.2 Scanning Electron Microscopy (SEM) Analysis 26 3.3 X-ray Photoelectron Spectroscopy (XPS) Analysis 29 3.4 Adhesion Results By Scotch Tape Test 31 3.5 Weight Loss Analysis 33 4. DISCUSSION 34 4.1 Contact Angle 34 4.2 Scanning Electron Microscopy (SEM) 35 4.3 X-ray Photoelectron Spectroscopy (XPS) 36 4.4 Adhesion Test 37 4.5 Weight Loss 39 5. CONCLUSION 40 SUGGESTIONS FOR FUTURE RESEARCH 42 REFERENCES 43 vi List of Tables 3.1 Contact angle (PTFE modified by helium microwave plasma) 23 3.2 Contact angle (PTFE modified by helium microwave plasma with O2 flowing over the substrate) 24 3.3 XPS analysis 29 Ar+ 3.4 Peel test on modified PTFE ( Cu deposited by assistant sputtering copper deposition system) 31 3.5 Weight loss analysis 33 vn List of Figures 1.1 Surface modification mechanism in the plasma 3 1.2 Vacuum UV radiation reaction procedures 4 1.3 Peel strengths of Cu, Al, Au, Cr and Ti deposited on PTFE, FEP and PFA film 6 1.4 Peel strength of Cu deposited on PTFE by Ar-ion(500ev) sputtering prior to the Cu deposition 7 2.1 Downstream microwave plasma system and reactor chamber 9 2.2 MW etching apparatus and reactor chamber 10 2.3 Aluminum holder and ring 11 2.4 Contact angle measurement 17 2.5 Sputtering chamber 18 2.6 Peel test 19 microwave 25 3.1 Contact angle (PTFE modified by Helium plasma) 3.2 Contact angle (PTFE modified by Helium microwave plasma with 02 flowing 25 over the substrate) 26 3.3 SEM analysis of Untreated PTFE MW plasma 27 3.4 SEM analysis of PTFE modified by 1 hr helium helium MW plasma 27 3.5 SEM analysis of PTFE modified by 2 hr MW plasma 28 3.6 SEM analysis of PTFE modified by 4 hr helium MW plasma with 3.7 SEM analysis of PTFE modified by 2 hr helium 02 Environments- -28 Vlll 3.8 XPS spectra of PTFE modified by downstream helium MW plasma with/without Q2 30 3.9 Copper film was totally peeled off from untreated PTFE surface 32 3.10 85% of the copper film was peeled off from the surface of PTFE modified by 2 hours helium MW plasma 32 3.11 85% of copper film was peeled off from the surface of PTFE modified by 4 hours helium MW plasma 32 3.12 5 % of the copper film was peeled off from the surface of PTFE modified by 2 hours helium MW plasma with oxygen 33 IX List of Abbreviations PTFE Polytetrafluoroefhylene VUV Vacuum Ultraviolet UV Ultraviolet MW Microwave He Helium IR Infrared Spectrum SEM Scanning Electron Microscopy XPS X-ray Photoelectron Spectroscopy ABSTRACT Teflon materials are well known for excellent thermal and chemical resistance properties. Their low dielectric constant makes them good materials for substrates in electronic packaging of microsystems where copper is often used as the conductor. Good adhesion between Cu and the hydrophobic PTFE is required in the microelectronics industry. A low-pressure helium MW plasma was used to modify the surface of PTFE located downstream from the plasma. Sometimes, oxygen was flowed over the surface of PTFE. Negligible photo-etching (< lnm/min) was observed. The contact angle of treated 04 PTFE film was found to decrease from an average value of 1 for untreated material to 86 an average of about and showed improved wettability with treatment time. Without modification, the adhesion of copper to PTFE was very weak. Significant improvement in adhesion occurs when PTFE is modified with VUV radiation downstream from a helium MW plasma with 02 flowing over the surface. SEM results show the modified PTFE has a rougher surface than untreated samples which provide more anchor sites to copper. XPS analysis shows defluorination and formation of oxygen-containing structures on the surface of the modified PTFE that contributes to the improved hydrophilic nature of the copper and modified PTFE. surface and stronger chemical bonding between the Trademark of E.I. Dupont De Nemours & Co., Wilmington, DE. xi 1. INTRODUCTION Teflon materials are well known for excellent thermal stability and chemical resistance. They are especially excellent insulators with low dielectric constants. The electronic package's signal transmission speed (v) is faster for lower dielectric constant Teflon (s) because v c< 1 1 4e . These properties make materials to be good potential substrates.1 Teflon polymers for microelectronic packaging However, materials have poor adhesion with metals due to low surface energy and poor wettability. Many attempts have been made to improve their adhesion to metals without changing their original excellent characteristics. Plasmas, ion beams, UV radiation, and wet chemical etching are Teflon commonly employed to alter the surface properties of materials. Modification of Teflon the surface of materials is often achieved by increasing the surface energy through the incorporation of new chemical functionalities, defluorination, oxidation, cross-linking, branching, or formation of unsaturated sites that help them bond to other materials and improve the adhesion of Teflon with metals. Several different approaches have been taken. Wet chemical etching of PTFE by sodium naphthalenide in (THF)2'3,4 ammonia5 tetrahydrofuran or sodium in liquid increase their ability to bond metals6'7 with other polymers or and results in a highly porous structure on fluoropolymer surfaces. At the same time, polymers could be partially defluorinated to a depth of 100 nm.2'3'4'5 nm to 1 000 But wet chemical etching treatment damages the bulk properties of the polymers. Etching depth on the surface is much more than by dry plasma etching and the affected layer will be markedly different from the bulk polymer. Further modification by irradiation or grafting is needed. Ar+ Treatment of samples with an ion plasma of energy 1 kV and pressure of copper.8 0.013-0.053 Pa in an oxygen environment enhance the adhesion with Downstream radiation from a helium microwave plasma [pressure of 240 Pa, microwave power of 1.0 kW, and helium flow rate of 0.25 liter/min] was found to modify the PTFE surface and cause defluorination. The MW plasma was formed in an aluminum tube trough' applicator.9 which passed through a 'double ridge plasma Ion bombardment initiates etching and leads to degradation products with small 104 molecular weight on the polymer surface; radiation from 6.7 x Pa He and Ar plasma generated by rotation Arc also contributes to ething10.
Load more

Recommended publications
  • Glossary Physics (I-Introduction)
    1 Glossary Physics (I-introduction) - Efficiency: The percent of the work put into a machine that is converted into useful work output; = work done / energy used [-]. = eta In machines: The work output of any machine cannot exceed the work input (<=100%); in an ideal machine, where no energy is transformed into heat: work(input) = work(output), =100%. Energy: The property of a system that enables it to do work. Conservation o. E.: Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes. Equilibrium: The state of an object when not acted upon by a net force or net torque; an object in equilibrium may be at rest or moving at uniform velocity - not accelerating. Mechanical E.: The state of an object or system of objects for which any impressed forces cancels to zero and no acceleration occurs. Dynamic E.: Object is moving without experiencing acceleration. Static E.: Object is at rest.F Force: The influence that can cause an object to be accelerated or retarded; is always in the direction of the net force, hence a vector quantity; the four elementary forces are: Electromagnetic F.: Is an attraction or repulsion G, gravit. const.6.672E-11[Nm2/kg2] between electric charges: d, distance [m] 2 2 2 2 F = 1/(40) (q1q2/d ) [(CC/m )(Nm /C )] = [N] m,M, mass [kg] Gravitational F.: Is a mutual attraction between all masses: q, charge [As] [C] 2 2 2 2 F = GmM/d [Nm /kg kg 1/m ] = [N] 0, dielectric constant Strong F.: (nuclear force) Acts within the nuclei of atoms: 8.854E-12 [C2/Nm2] [F/m] 2 2 2 2 2 F = 1/(40) (e /d ) [(CC/m )(Nm /C )] = [N] , 3.14 [-] Weak F.: Manifests itself in special reactions among elementary e, 1.60210 E-19 [As] [C] particles, such as the reaction that occur in radioactive decay.
    [Show full text]
  • Hydrogen Bond Assisted Adhesion in Portland Cement-Based Materials
    136 Cerâmica 57 (2011) 136-139 Hydrogen bond assisted adhesion in Portland cement-based materials (Adesão assistida por ligação de hidrogênio em materiais à base de cimento Portland) H. L. Rossetto1,2, V. C. Pandolfelli1 1Departamento de Engenharia de Materiais - DEMa, Universidade Federal de S. Carlos - UFSCar, Rod. Washington Luiz, km 235, S. Carlos, SP 13565-590 2Instituto de Física de S. Carlos, Universidade de S. Paulo - IFSC-USP, Av. Trabalhador São-Carlense 400, S. Carlos, SP 13566-590 [email protected] Abstract Adhesion is a physical-chemical parameter able to render innovations to Portland cement-based materials. However, this concept still lacks experimental evidence to underlie further developments in this subject. This work has demonstrated how distinct substances can impart different adhesion forces after evaluating the hydration degree and the mechanical strength of non-reactive cementitious materials. The substances capable of making tridimensional hydrogen bonds, such as water, for instance, were the most effective in providing cementitious samples with improved bending strength. It implies that water is not only important because of its role in cement hydration, but also because it develops adhesion between hydrated cementitious surfaces. More than speculating the fundamental understanding on adhesion in Portland cement-based materials, the present paper intends to stimulate thinking on how to take the benefits of the water confined between the hydrated cementitious surfaces as an in-built nanoadhesive, so far little explored, but at the same time so prone to yield high performance materials. Keywords: adhesion, hydrogen bond, mechanical properties, Portland cement. Resumo Adesão é um parâmetro físico-químico que pode promover inovações em materiais à base de cimento Portland.
    [Show full text]
  • UNIVERSITY of CALIFORNIA, IRVINE Kinetic Studies Of
    UNIVERSITY OF CALIFORNIA, IRVINE Kinetic Studies of Multivalent Nanoparticle Adhesion DISSERTATION submitted in partial satisfaction of the requirements for the deGree of DOCTOR OF PHILOSOPHY in Biomedical EnGineerinG by MinGqiu WanG Dissertation Committee: Assistant Professor Jered Haun, Chair Associate Professor Jun Allard Professor YounG Jik Kwon 2018 © 2018 MinGqiu WanG DEDICATION To my parents, for their unconditional love and support. ii TABLE OF CONTENTS DEDICATION.......................................................................................................................... II TABLE OF CONTENTS........................................................................................................ III LIST OF FIGURES .................................................................................................................. V LIST OF TABLES ................................................................................................................. VII ACKNOWLEDGMENTS ..................................................................................................... VIII CURRICULUM VITAE ........................................................................................................... X ABSTRACT OF THE DISSERTATION ............................................................................... XI 1. INTRODUCTION ........................................................................................................... 1 1.1. TARGET NANOPARTICLE ADHESION ............................................................................................
    [Show full text]
  • Adhesion and Cohesion
    Hindawi Publishing Corporation International Journal of Dentistry Volume 2012, Article ID 951324, 8 pages doi:10.1155/2012/951324 Review Article Adhesion and Cohesion J. Anthony von Fraunhofer School of Dentistry, University of Maryland, Baltimore, MD 21201, USA Correspondence should be addressed to J. Anthony von Fraunhofer, [email protected] Received 18 October 2011; Accepted 14 November 2011 Academic Editor: Cornelis H. Pameijer Copyright © 2012 J. Anthony von Fraunhofer. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its impor- tance with regard to adhesive dentistry and bonding to enamel and dentin is discussed. 1. Introduction molecular attraction by which the particles of a body are uni- ted throughout the mass. In other words, adhesion is any at- Every clinician has experienced the failure of a restoration, be traction process between dissimilar molecular species, which it loosening of a crown, loss of an anterior Class V restora- have been brought into direct contact such that the adhesive tion, or leakage of a composite restoration.
    [Show full text]
  • Unique Properties of Water!
    Name: _______ANSWER KEY_______________ Class: _____ Date: _______________ Unique Properties of Water! Word Bank: Adhesion Evaporation Polar Surface tension Cohesion Freezing Positive Universal solvent Condensation Melting Sublimation Dissolve Negative 1. The electrons are not shared equally between the hydrogen and oxygen atoms of water creating a Polar molecule. 2. The polarity of water allows it to dissolve most substances. Because of this it is referred to as the universal solvent 3. Water molecules stick to other water molecules. This property is called cohesion. 4. Hydrogen bonds form between adjacent water molecules because the positive charged hydrogen end of one water molecule attracts the negative charged oxygen end of another water molecule. 5. Water molecules stick to other materials due to its polar nature. This property is called adhesion. 6. Hydrogen bonds hold water molecules closely together which causes water to have high surface tension. This is why water tends to clump together to form drops rather than spread out into a thin film. 7. Condensation is when water changes from a gas to a liquid. 8. Sublimation is when water changes from a solid directly to a gas. 9. Freezing is when water changes from a liquid to a solid. 10. Melting is when water changes from a solid to a liquid. 11. Evaporation is when water changes from a liquid to a gas. 12. Why does ice float? Water expands as it freezes, so it is LESS DENSE AS A SOLID. 13. What property refers to water molecules resembling magnets? How are these alike? Polar bonds create positive and negative ends of the molecule.
    [Show full text]
  • Multidisciplinary Design Project Engineering Dictionary Version 0.0.2
    Multidisciplinary Design Project Engineering Dictionary Version 0.0.2 February 15, 2006 . DRAFT Cambridge-MIT Institute Multidisciplinary Design Project This Dictionary/Glossary of Engineering terms has been compiled to compliment the work developed as part of the Multi-disciplinary Design Project (MDP), which is a programme to develop teaching material and kits to aid the running of mechtronics projects in Universities and Schools. The project is being carried out with support from the Cambridge-MIT Institute undergraduate teaching programe. For more information about the project please visit the MDP website at http://www-mdp.eng.cam.ac.uk or contact Dr. Peter Long Prof. Alex Slocum Cambridge University Engineering Department Massachusetts Institute of Technology Trumpington Street, 77 Massachusetts Ave. Cambridge. Cambridge MA 02139-4307 CB2 1PZ. USA e-mail: [email protected] e-mail: [email protected] tel: +44 (0) 1223 332779 tel: +1 617 253 0012 For information about the CMI initiative please see Cambridge-MIT Institute website :- http://www.cambridge-mit.org CMI CMI, University of Cambridge Massachusetts Institute of Technology 10 Miller’s Yard, 77 Massachusetts Ave. Mill Lane, Cambridge MA 02139-4307 Cambridge. CB2 1RQ. USA tel: +44 (0) 1223 327207 tel. +1 617 253 7732 fax: +44 (0) 1223 765891 fax. +1 617 258 8539 . DRAFT 2 CMI-MDP Programme 1 Introduction This dictionary/glossary has not been developed as a definative work but as a useful reference book for engi- neering students to search when looking for the meaning of a word/phrase. It has been compiled from a number of existing glossaries together with a number of local additions.
    [Show full text]
  • Hydraulics Manual Glossary G - 3
    Glossary G - 1 GLOSSARY OF HIGHWAY-RELATED DRAINAGE TERMS (Reprinted from the 1999 edition of the American Association of State Highway and Transportation Officials Model Drainage Manual) G.1 Introduction This Glossary is divided into three parts: · Introduction, · Glossary, and · References. It is not intended that all the terms in this Glossary be rigorously accurate or complete. Realistically, this is impossible. Depending on the circumstance, a particular term may have several meanings; this can never change. The primary purpose of this Glossary is to define the terms found in the Highway Drainage Guidelines and Model Drainage Manual in a manner that makes them easier to interpret and understand. A lesser purpose is to provide a compendium of terms that will be useful for both the novice as well as the more experienced hydraulics engineer. This Glossary may also help those who are unfamiliar with highway drainage design to become more understanding and appreciative of this complex science as well as facilitate communication between the highway hydraulics engineer and others. Where readily available, the source of a definition has been referenced. For clarity or format purposes, cited definitions may have some additional verbiage contained in double brackets [ ]. Conversely, three “dots” (...) are used to indicate where some parts of a cited definition were eliminated. Also, as might be expected, different sources were found to use different hyphenation and terminology practices for the same words. Insignificant changes in this regard were made to some cited references and elsewhere to gain uniformity for the terms contained in this Glossary: as an example, “groundwater” vice “ground-water” or “ground water,” and “cross section area” vice “cross-sectional area.” Cited definitions were taken primarily from two sources: W.B.
    [Show full text]
  • Glossary of Terms
    Glossary of English/Spanish Superfund & WQARF Terms (Note: You may access the bookmark menu at the left to navigate this document more efficiently.) Any ADEQ translation or communication in a language other than English is unofficial and not binding on the State of Arizona. Cualquier traducción o comunicado de ADEQ en un idioma diferente al inglés no es oficial y no sujetará al Estado de Arizona a ninguna obligación jurídica. A Absorption: The passage of one substance into or through another. Absorción: Absorción es el paso de una sustancia a través de otra. Acre-foot: A quantity or volume of water covering one acre to a depth of one foot; equal to 43,560 cubic feet or 325,851 gallons. Acre-pie: Una cantidad o volumen de agua que cubre un acre a una profundidad de un pie; es un equivalente a 43.560 pies cúbicos o 325.851 galones. Activated Carbon: Adsorptive particles or granules of carbon usually obtained by heating carbon (such as wood). These particles or granules have a high capacity to selectively remove certain trace and soluble materials from water. Carbono Activo: Partículas or gránulos de carbono que se obtienen generalmente por medio del calentamiento de carbono (como la madera). Estas partículas o gránulos tienen una alta capacidad de eliminar selectivamente ciertos rastros y materiales solubles del agua. Acute: Occurring over a short period of time; used to describe brief exposures and effects which appear promptly after exposure. Grave: Ocurre durante corto tiempo; se usa para describir breves exposiciones y los efectos que aparecen rapidamente después de una sola exposición.
    [Show full text]
  • A Review of Cell Adhesion Studies for Biomedical and Biological Applications
    Int. J. Mol. Sci. 2015, 16, 18149-18184; doi:10.3390/ijms160818149 OPEN ACCESS International Journal of Molecular Sciences ISSN 1422-0067 www.mdpi.com/journal/ijms Review A Review of Cell Adhesion Studies for Biomedical and Biological Applications Amelia Ahmad Khalili 1 and Mohd Ridzuan Ahmad 1,2,* 1 Department of Control and Mechatronic Engineering, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor 81310, Malaysia; E-Mail: [email protected] 2 Institute of Ibnu Sina, Universiti Teknologi Malaysia, Johor 81310, Malaysia * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +607-553-6333; Fax: +607-556-6272. Academic Editor: Fan-Gang Tseng Received: 10 May 2015 / Accepted: 24 June 2015 / Published: 5 August 2015 Abstract: Cell adhesion is essential in cell communication and regulation, and is of fundamental importance in the development and maintenance of tissues. The mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. The essential function of cell adhesion has created tremendous interests in developing methods for measuring and studying cell adhesion properties. The study of cell adhesion could be categorized into cell adhesion attachment and detachment events. The study of cell adhesion has been widely explored via both events for many important purposes in cellular biology, biomedical, and engineering fields. Cell adhesion attachment and detachment events could be further grouped into the cell
    [Show full text]
  • Adhesive Bonding of Polyolefin Edward M
    White Paper Adhesives | Sealants | Tapes Adhesive Bonding of Polyolefin Edward M. Petrie | Omnexus, June 2013 Introduction Polyolefin polymers are used extensively in producing plastics and elastomers due to their excellent chemical and physical properties as well as their low price and easy processing. However, they are also one of the most difficult materials to bond with adhesives because of the wax-like nature of their surface. Advances have been made in bonding polyolefin based materials through improved surface preparation processes and the introduction of new adhesives that are capable of bonding to the polyolefin substrate without any surface pre-treatment. Adhesion promoters for polyolefins are also available that can be applied to the part prior to bonding similar to a primer. Polyolefin parts can be assembled via many methods such as adhesive bonding, heat sealing, vibration welding, etc. However, adhesive bonding provides unique benefits in assembling polyolefin parts such as the ability to seal and provide a high degree of joint strength without heating the substrate. This article will review the reasons why polyolefin substrates are so difficult to bond and the various methods that can be used to make the task easier and more reliable. Polyolefins and their Surface Characteristics Polyolefins represent a large group of polymers that are extremely inert chemically. Because of their excellent chemical resistance, polyolefins are impossible to join by solvent cementing. Polyolefins also exhibit lower heat resistance than most other thermoplastics, and as a result thermal methods of assembly such as heat welding can result in distortion and other problems. The most well-known polyolefins are polyethylene and polypropylene, but there are other specialty types such as polymethylpentene (high temperature properties) and ethylene propylene diene monomer (elastomeric properties).
    [Show full text]
  • Adhesion to Plastic
    Adhesion to Plastic Marcus Hutchins Scientist I TS&D Industrial Coatings-Radcure Cytec Smyrna, GA USA Abstract A plastic can be described as a mixture of polymer or polymers, plasticizers, fillers, pigments, and additives which under temperature and pressure can be molded into various items1. Plastic materials have become a staple of our everyday life in applications ranging from food packaging to home construction. In automotive applications alone, over four billion pounds2 of plastic were used in cars and light trucks and that figure is expected to grow 30 percent by 2011. The demand for plastic is growing at a rate faster than metal because of advantages such as reduced weight, reduced material cost, corrosion resistance and increased durability over metal. As the demand for plastic increases, the need to effectively and efficiently coat plastic parts will also increase. For most plastics, that will mean starting with a good primer coating. This paper will present three new ultraviolet (UV) curable resins that may be used to formulate primers for a variety of plastic substrates. ©RadTech e|5 2006 Technical Proceedings Introduction Once a plastic part is formed, a coating is usually applied for decorative or protective purposes. Typically, that starts with a primer coating. There are many factors that positively affect the adhesion of the primer to the substrate, and several will be discussed here. One of the more important properties in achieving adhesion is the ability of the coating to wet the substrate3. In order for wetting to occur, the surface tension of the coating must be less than the surface energy of the substrate.
    [Show full text]
  • Wetting and Phase Separation in Soft Adhesion
    Wetting and phase separation in soft adhesion Katharine E. Jensena, Raphael Sarfatia, Robert W. Styleb, Rostislav Boltyanskiya, Aditi Chakrabartic, Manoj K. Chaudhuryc, and Eric R. Dufresnea,1 aDepartment of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06511; bMathematical Institute, University of Oxford, Oxford, OX1 3LB, United Kingdom; and cDepartment of Chemical Engineering, Lehigh University, Bethlehem, PA 18015 Edited by Joanna Aizenberg, Harvard University, Cambridge, MA, and accepted by the Editorial Board October 13, 2015 (received for review July 22, 2015) In the classic theory of solid adhesion, surface energy drives line between a rigid indenter and a soft substrate should be de- deformation to increase contact area whereas bulk elasticity termined by a balance of surface stresses and surface energies, just opposes it. Recently, solid surface stress has been shown also to as the Young–Dupré relation sets the contact angle of a fluid on a play an important role in opposing deformation of soft materials. rigid solid (31). However, the structure of the contact zone in soft This suggests that the contact line in soft adhesion should mimic adhesion has not been examined experimentally. that of a liquid droplet, with a contact angle determined by surface In this article, we directly image the contact zone of rigid tensions. Consistent with this hypothesis, we observe a contact spheres adhered to compliant gels. Consistent with the domi- angle of a soft silicone substrate on rigid silica spheres that nance of surface stresses over bulk elastic stresses, we find that depends on the surface functionalization but not the sphere size.
    [Show full text]