ABSTRACTS
The following is a list of the abstracts for papers which will be presented in the SECOND INTERNATIONAL SYMPOSIUM ON POLYMER SURFACE CHARACTERIZATION 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) Department of Materials Engineering and Laboratory for
Surface Studies, University of Wisconsin-Milwaukee, P.O. Box 784,
Milwaukee, WI 53201
2) AMPAC and MMAF, University of Central Florida, Orlando, Florida
3) Department of Chemistry, University of Cambridge, Cambridge, U.K.
XPS Characterization of the Inorganic Polymer Chemistry Exhibited by Geo Silicates
It is generally held that polymeric materials involved repetitious organic units. However, it is not required that the basic (mer) units be organic. In fact many of the best examples of polymers are inorganic and some of these are even fundamental to the geological system of terrestrial planets, long predating man and his ego.
The disadvantages of many of the inorganic materials are that they often preclude any ready form of controlled growth or modification. The advantage on the other hand, is that many of their properties may be readily differentiated by relatively straightforward analysis methods, such as x-ray photoelectron spectroscopy (XPS).
The polymerization referred to herein is built up around the tetrahedral silicate bond often augmented by key aluminate units.
The concept of polymerization generally suggests more involved geometric structures (chains, rings, sheets, etc.) often with the mixed incorporation of tetrahedral silicates and aluminates and octahedral aluminates, magnesiates, ferrates, etc. As suggested above XPS analysis of silicate polymerization is more readily detected than that for organic polymer units, however, as described herein, it has become apparent that similarities have made it possible to use comparative silicate/carbon results to predict accurately in both areas. As in the case of organic polymers, critical features regarding formation, modification termination and often properties may be read from comparative XPS analysis.
Sandia National Laboratories, Albuquerque, NM
IFM Studies of Polymer Interfaces: Implications for Microfluidic Systems
Sandia is developing microfluidic systems to manipulate biomolecules for applications ranging from counter-terrorism to implantable drug delivery systems. Protein-handling systems require anti-fouling coatings such as polyethylene oxide (PEO), and polymers such as poly(n-isopropylacrylamide (PNIPAM) that can be switched to grab and release proteins on command. We are probing how such coatings modify surface chemistry using a scanning probe system called the interfacial force microscope (IFM). The IFM enables us to measure forces between materials in water at separation distances of a few atomic layers. IFM measurements show that PEO generates a repulsive hydration force that inhibits protein adsorption. Variable speed IFM measurements show that this hydration force is associated with the presence of an ordered "interphase" of water that is over 30 water molecules thick and has a viscosity that is over one million times greater than that of bulk water. IFM measurements on PNIPAM show that at room temperature, films of this polymer are swollen with water to create a barrier to proteins similar to that seen on PEO. However, above a transition temperature of 30oC, the polymer collapses to form surface that can readily adsorb protein monolayers, forming the basis for a reversible protein trap.
Polymeric Materials: A New Class of Adsorbent for Surface Processes
Polymeric materials are used for variety of technological applications across a wide range of disciplines. Appropriate control of their surface and interfacial characteristics is of vital importance for their use1. Thus, from the practical point of view, it is important to improve the surface properties of polymeric materials that already exist. It is also necessary to explore more new polymeric materials for their wider and effective applications. Indeed, new conducting polymers with modified architecture, possibility of immobilizing metallic particles inside the polymer, polymer/polymer composites etc. have already been reported to be the useful polymeric materials2-4.
In the present research, polyaniline/silica (PANI/silica) composite has been prepared under a variety of synthetic conditions by polymerizing the monomer in the presence of silica prepared in situ from an aqueous sodium silicate solution. The composite thus synthesized has been characterized by a wide range of experimental techniques including elemental analysis for silica content, density measurements, IR spectroscopy and sedimentometry for particle size determination.
PANI/silica sample has been tested as column material for the separation of alkanes (C5 - C9) by inverse gas chromatography (IGC). The composite has found to be capable of separating the alkanes from their mixture. The composite has been further examined for their surface free energy and specific surface area. The observed BET surface area of the composite has been found to be nearly ten times higher than that of the polymer itself. In this respect, adsorption of methylene blue on the PANI/silica surface has been studied in some details.
References
1.K. L. Mittal and K.-W. Lee (eds.), Polymer Surfaces and Interfaces: Characterization, Modification and Application, VSP, 1997.
2.J. W. Thackeray and M. S. Wrighton, J. Phys. Chem., 1986, 90, 6674.
3.J. Guay, R. Paynter and L. H. Dao, Macromolecules,1990, 23, 3598.
4.T. K. Mandal and B. M. Mandal, Synth. Met., 1996, 80, 83.
Polymer Surface Characterization by TOF-SIMS
Time of Flight - Secondary Ion Mass Spectrometry (TOF-SIMS) has been widely used in polymer analysis. It can provide important information such as elemental distribution, functional group identification, and backbone structure. Because of its high surface sensitivity, TOF-SIMS is a powerful technique to characterize the surface composition and contamination on polymer materials. The results can help better understand a variety of surface related properties such as adhesion, wettability and lubrication. In this study, a variety of polymer materials were examined by TOF-SIMS. Polymer structures were identified based on their unique fragment peaks. In addition, polymer additives, surface contamination, and copolymer segregation were investigated.
Surface Glass Transition on untreated and Ion-Beam Modified Polymer Surfaces
(Abstract not yet available)
Condensation Coefficients of Metals on Polymer Surfaces
(Abstract not yet available)
Type and Density Variable Polymer Surface Functionalization of Polymers
(abstract not yet available)
1) Radiation and Polymer Chemistry Laboratory, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka, BANGLADESH
2) Department of Chemistry, Jahangirnagar University, Savar, Dhaka, Bangladesh, 2 Bangaldsesh Jute Research Institute, Dhaka, BANGLADESH
Surface Characterization of Photo-grafted Jute Yarn with Silane and Acrylic Monomers
Jute yarns were grafted with five types of silane monomers of various functionalities such as g-aminopropyl trimethoxy silane (Z-6011), N-(b-amino ethyk) g-aminopropyl trimethoxy silane (Z-6020), g-methacrylate propyl trimethoxy silane (Z-6030), 3-glycidoxypropyl trimethoxy silane (Z-6040) and vinyl trimethoxy silane (Q9-6300) and two types of acrylic monomers of different functional groups like 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AM)) by using UV radiation in order to improve the mechanical properties. The physico-mechanical properties such as tensile strength, elongation at break of grafted jute yarn have been investigated. A series of solutions of different monomers of various concentrations in methanol along with photoinitiator (Irgacure-907, 2%) were prepared. The jute yarns were soaked in the solution for 15 hour before radiation. The effect of irradiation time, concentration of monomer on polymer loading and tensile properties of the jute yarn were studied. Silane monomer particularly g-aminopropyl trimethoxy silane (Z-6011) should the best performance among all the monomers considered. To study the chemical environment of the surfaces of both treated and untreated jute were characterized by X-ray photo-spectrometer (XPS), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM), differential scanning calorimetry (DSC) and observed that the both silane or vinyl monomers reacted or deposited on jute surface.
1) Department of Mechanical Engineering, National University of Singapore, Engineering Drive 2, Singapore 119260
2) Department of Chemical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
Surface and Interface Characterization of Sputter-Deposited Fluoropolymer Films
Dielectric polymer films of about 40 to 300 nm in thickness were deposited on the Si(100) substrates via RF plasma sputtering of various fluoropolymer targets, including poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-co- hexafluoropropylene) (FEP), and fluorinated polyimides (FPI). X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), water contact angle measurement, and Fourier transform infrared (FTIR) spectroscopy results indicated that the chemical composition and molecular structure of the sputter-deposited fluoropolymer films depended strongly on the type of the sputtering gas used. The dielectric constant (k value) and the deposition rate of the resulting fluoropolymer films were also found to be dependent on the type of the sputtering gas. The fluoropolymer film deposited via sputtering of a PTFE target by CF4 plasma had a k value of 1.9, which was even lower than that of the pristine PTFE film (k=2.0-2.1). On the other hand, the non-reactive Ar plasma gave rise to the highest deposition rate among the various sputtering gases used. Peel adhesion test results indicated that all the sputter-deposited films adhered strongly to the Si(100) surfaces.
Surface Properties of Polymers Treated by Plasma Source Ion Implantation (PSII)
The Plasma Source Ion Implantation (PSII) technique has been utilized to improve the hardness, friction, wear and corrosion properties of various material surfaces, and to substitute the doping steps in semiconductor manufacturing. Recently, our group investigated the use of PSII in the modification of polymeric materials. Synthetic polymers such as polyimide, polystyrene, poly(ethylene terephthalate), modified poly(phenylene oxide), low-density polyethylene, and ionomers were used for investigations. They were implanted with different ion species such as Ar, Xe, N2, O2, and CF4 to render the surface more hydrophilic or hydrophobic. Hydrophobic recoveries of PSII-treated polymers were observed as a function of aging time, temperature, and treatment parameters. Treatment parameters include kinds of gases, gas pressure, plasma power, pulse frequency, pulse width, ion energy, etc. In this study we also provide a method for surface modification of 3-dimensional bulk polymers, which is capable of implanting plasma ions into surface of 3-dimensional bulk polymer sample by mounting a metallic grid over a sample stage. The effect of ion energy, treatment time, rf frequency, power on the surface resistivity of polymer was investigated. Depending on ion energy, dose, and ion species, the surface resistivity of the film was reduced by several orders of magnitude. Hydrophilic property and electrical property improvement was measured by water contact angle goniometer and high resistance electrometer, respectively. Surface techniques including XPS, TOF-SIMS, and SEM were used to characterize the polymer surfaces treated by PSII.
1) IMEC, Kapeldreef 75,B-3001 Leuven, BELGIUM
2) K.U.Leuven, MTM, Kasteelpark Arenberg 44, B-3001 Leuven, BELGIUM
A Novel Approach to Characterise a Low-k Dielectric Polymer Surface
(abstract not yet Available)
Developing and Characterising Biospecific Surfaces
(Abstract not yet available) WITHDRAWN
Sum-Frequency Vibrational Spectroscopy of Poymer Surfaces for Liquid Crystal Alignment
Surface specific sum-frequency vibrational spectroscopy (SFVS) and second-harmonic generation were used to study how various polymer surfaces can be affected by mechanical rubbing or linearly polarized UV irradiation, and how the modified surface structures align a liquid crystal film deposited on them.
We have studied the CO stretch modes from a rubbed polyimide surface. The spectra show explicitly the existence of rubbing-induced anisotropy in the surface structure of polyimide. We also measured the spectra of CH stretch modes of the side chains to study how the alkyl side chains are oriented atthe surface after rubbing. In this case, the spectra hardly show the existence of rubbing-induced anisotropy. The SFVS from polyimide for different input/output polarization combinations and sample orientations have been measured before and after UV irradiation. The results show that the peak intensities of phenylene skeleton C-C stretch and imide C=O stretch modes are significantly reduced after UV irradiation, indicating that the observed peak reduction in the spectra is not due to photo-induced reorientation of the relevant atomic groups, but due to photo-induced bond breaking.
We have also studied the structure of a rubbed polystyrene surface. The results show that the phenyl sidegroups are well aligned by rubbing in the direction perpendicular to rubbing but tilt from the surface normal with a broad distribution.
1) NASA, Spaceport Engineering and Technology Directorate, Kennedy Space Center, FL, 32899
2) NASA, Mail Stop 226, Langley Research Center, Hampton, VA 23681
3) Albion College, Chemistry Department, 611 E. Porter St., Albion, MI, 49224
4) Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901
A Characterization Study of Polyimide Foams after Exposure to Extreme Weathering Conditions
The surface and sub-surface weathering degradation of three closely related polyimide foams was studied by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (IR) and Raman Spectroscopies, and Thermogravimetric (TGA) and mechanical (TMA) analyses after exposure at the NASA Kennedy Space Center's Beach Corrosion site. These foams developed by NASA Langley Research Center have been developed for applications such as cryogenic insulation, flame retardant panels and structural subcomponents. The aggressive weather conditions at the KSC corrosion site include exposure to sunlight, exposure to changes in temperature and humidity, mechanical erosion and unique atmospheric contaminants such as the space shuttle and rockets exhausts. Surface characterization changes are analyzed and discussed using high resolution XPS and Raman, with both surface and sub-surface degradation observed using IR and thermal analyses. The overall degradation process is studied for a 17 months exposure, with differences in chemical structure versus density effects playing the greatest role in weathering performance.
Surface Characterization Study of Biodegradable Polymers
Contact angle is a very significant parameter in surface science, and is a commonly used measurement of the hydrophobicity of solid surfaces. The research work reported in this paper focuses on the wettability of the surfaces of five different biodegradable polymers, namely Poly (lactic-co-glycolic acid) PLGA 75:25, PLGA 65:35, PLGA 50:50, Poly ortho ester (POE) and Poly ethylene glycol (PEG). The static contact angles were measured using goniometer and with glycerol and diiodomethane as the testing liquids. The results obtained indicate that the polar component of the solid surface energy of the PLGA increases as the percentage of poly glycolic acid is increased. In addition, the polar component of the solid surface energy of POE is quite low like the PLGA with higher lactic acid content. Whereas it is high in the case of PEG like the PLGA with high glycolic acid content. Atomic Force Microscope (AFM) and X-ray Photoelectron Spectroscope (XPS) were utilised to monitor the surface morphology and compositions of these biopolymers.
Surface Study of 6FDA-based Polyetherimides
(Abstract not yet available)
1) Heriot-Watt University, School of Textiles, Netherdale, Galashiels, TD1 3HF, United Kingdom
2) Heriot-Watt University, Department of Mechanical and Chemical Engineering, Riccarton, Edinburgh, EH14 4AS, UK
3) Heriot-Watt University, Department of Petroleum Engineering, Riccarton, Edinburgh, EH14 4AS, UK
Ex-situ and In-situ Observation of Necking in Polypropylene Fibres Using Advanced Microscopy Techniques
The paper aims to demonstrate how Scanning Probe Microscopy (SPM), notably in the form of Atomic Force Microscopy (AFM) (contact mode) supported by Lateral Force Microscopy (LFM), and Environmental Scanning Electron Microscopy (ESEM) can provide new and complementary information regarding the structural development of polypropylene (PP) fibres during neck formation. An understanding of structural changes during necking may provide a means of evaluating polymers for various tensile deformation processes and assist optimisation of processing conditions. A purpose built tensile stage for the ESEM has enabled necking stress to be observed in real time. The deformation of spherulites with subsequent formation of fibrils was seen for both gravity spun and as spun PP fibres during the necking process. The formation of voids in the necking region was observed in the case of gravity spun filaments, but not for as spun variants. Areas of particular interest were imaged and analysed with SPM before and after necking. The surface morphology of the gravity spun and as spun fibres was found to be spherulitic before necking, with a similar subspherulitic structure for both variants. However, results from X-ray diffraction analysis indicate contrasting features between bulk and surface crystalline structure. Longitudinal and transverse cross-sections were therefore prepared to obtain further information on the difference between internal- and surface structure at various stages during processing.
E. S. Valamontes; Technological Educational Institute of Athens, 12210 Aegaleo, GREECE POSTER
Surface Roughness Induced by Plasma Etching on Si-containing Polymers
Interface properties of polymers and their control become important at submicron scales, as polymers find widespread applications from micro- and nano-electronics to optoelectronics and other industrial fields. In this work, we address the issue of controlled modification of surface topography of Si-containing polymers when subjected to oxygen-based plasma treatments. Treated surfaces are examined by Atomic Force Microscopy to obtain surface topography and roughness, while statistical analysis is performed on acquired images to reveal the scaling behaviour of plasma-treated surfaces. Our experimental results indicate that appropriate optimization of plasma chemistry and processing conditions allows, on one hand, small values of surface roughness, a result crucial for the potential use of these polymers for sub-100 nm lithography, and on the other hand, when desirable, important topography, applicable for example in sensor devices. In more detail, plasma processing conditions can be modified to result either in smooth self-affine surfaces (rms roughness <1 nm) or in periodic mound structures of controlled roughness size and periodicity (rms roughness up to tens of nm, and periodicity of several hundreds nm). Finally, the mechanisms involved in the modification of the polymer surface topography during plasma treatment will be discussed and correlated to the plasma treatment conditions.
1) Department of Polymer Science and Engineering, The State Key Laboratory of Coordinate Chemistry,Nanjing University, Nanjing, 210093, P. R. CHINA
2) Department of Polymer Science, the University of Akron, Akron, OH, 44325-3909
Molecular Orientation and Relaxation on a Surface of a Thin Film of Polymeric Liquid Crystalline
Surface molecular orientation and relaxation of aromatic polyimide liquid crystalline containing pendent cyanobiphenyl mesogens in thin films were investigated by surface enhanced Raman scattering (SERS) using silver particles as over-coating layer which was chemically deposited from a solution. SERS measurements for sample of current interest, such as ultra-thin polyimide film, were successfully performed without disturbing the surface morphology. The results of this work show that our SERS sampling technique is particularly effective for surface study on polymer films.