EIGHTH INTERNATIONAL SYMPOSIUM ON
SILANES AND OTHER COUPLING AGENTS
June 22-24, 2011
Danbury, Connecticut, USA
SYMPOSIUM HISTORY AND MOTIVIATION
This symposium continues the tradition set by the first symposium in this series:”Silanes and Other Coupling Agents” which was hosted in 1991 by the Dow Corning Corporation in honor of Dr. Edwin P. Plueddemann. As with its predecessors, this symposium is concerned with the technological areas where the use of surface primers such as silanes is critical to the success of many technologies.
Historically the silanes have been used as coupling agents for thin films in the microelectronics industry and in glass fiber composites where the use of silanes has been an enabling factor in the success of many manufactured products. Quite surprisingly, silanes have also found a role in biotechnology as specific coupling agents for bonding polynucleotides to the so-called “gene chips” and also in cosmetic applications.
Listed below are the papers presented at the Eighth International symposium on Polymer Surface Modification held at the Danbury Plaza Hotel, Danbury Connecticut the week of June 20, 2011. To view the abstract click on the name of the highlighted author. In some cases the author has made his presentation slides available in .pdf format. In such cases the title is highlighted and clicking on it will bring up the presentation. Please note that these presentations are being made available as
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WEDNESDAY, JUNE 22, 2011
(JOINT SESSION WITH POLYMER SURFACE MODIFICATION PROGRAM)
9:00-9:30am: Stephen Coulson; P2i Ltd., 127 North, Milton Park, OX14 4 SA, Abingdon, Oxfordshire, UK; Plasma Surface Modification for Increased Hydrophilicity
9:30-10:00: Mikko Tuominen, Hannu Teisala, Mikko Aromaa, Milena Stepien, Jyrki M. Mäkelä, Jarkko J. Saarinen, Martti Toivakka and Jurkka Kuusipalo; Paper Converting and Packaging Technology, Tampere University of Technology,P.O.Box 541, FI-33101 Tampere, FINLAND; Generation and Stimulation of Liquid Flame Spray (LFS) Coating
10:00-10:30: Saswati Datta; Procter and Gamble , Miami Valley Innovation Center, 11810 East Miami River Road, Cincinnati OH 45252; "Skin Mimic": Surface Modification of Polymers to Mimic Human Skin firstname.lastname@example.org
10:30-11:00: COFFEE BREAK
11:00-11:30: Shubhra Gangopadhyay,
Venu Korampally, Singdha Praharaj, Vamsi Mamidi, Bryant Harris, Luis Polo Parada, Sangho Bok and Keshab Gangopadhyay University of Missouri, Columbia, MO; Polymethyl Silsesquioxane Nanoparticles, their Surface Modifications and Applications in Microsystems
11:30-12:00: N. De Geyter, R. Morent,
T. Jacobs, S. Van Vlierberghe, P. Dubruel and Christophe Leys; Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering, Ghent University, Jozef Plateaustraat 22, 9000 Gent, BELGIUM; Medium Pressure Plasma Treatment of Biodegradable PLA and PCL
12:00-12:30: Kerry A. Wilson, Craig A. Finch, Phillip Anderson, James J. Hickman and Frank Vollmer; NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando FL 32828; Quantification and Structure Evaluation of Protein Adsorbed at Defined Interfaces and its Effect on Subsequent Cell Culture email@example.com
12:30-2:00: LUNCH BREAK
WEDNESDAY, JUNE 22, 2011
2:00-2:30: Shantanu Bhattacharya; Department of Mechanical Engineering, IIT Kanpur, INDIA; Plasma Modification of Polymer Surfaces and Their Utility in Building Biomedical Microdevices
2:30-3:00: X. F. Hu, F. Zhang, E. T. Kang and
K. G. Neoh; Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260; Exploiting Surface Chemical Modification of Natural Biopolymers for Selective Bio-interactivity with Bacteria and Bone Cells in Orthopedic Applications firstname.lastname@example.org
3:00-3:30: K. Fricke, K. Duske, A. Quade, B. Nebe, K. Schröder and Th. v. Woedtke; Leibniz Institute for Plasma Science and Technology (INP Greifswald e.V.), Greifswald, GERMANY; Comparison of Low-temperature Plasma Processes on the Surface Properties of Polystyrene and Their Impact on the Growth of Osteoblastic Cells
NOVEL APPLICATIONS OF SILANES
9:00-9:05: INTRODUCTORY REMARKS
9:05-9:35: Bret Chisholm, Partha Majumdar, Shane Stafslien, and David Christianson; Center for Nanoscale Science and Engineering, North Dakota State University, Fargo, ND; An Investigation of Antimicrobial Coatings Derived from Quaternary Ammonium-Functional Alkoxysilanes Using Combinatorial/High-Throughput Methods
9:35-10:05: A. Ansarifar; Materials Department, Loughborough University, Leicestershire LE11 3TU, UK; How a Sulfur-Bearing Bifunctional Organosilane Changed the Shape of Rubber Formulation email@example.com
10:05-10:35: W. Dierkes, M. Tiwari, R. Datta, A. Talma, J. Noordermeer and W. van Ooij; University of Twente, Faculty of Engineering Technology, Department of Elastomer Technology & Engineering, Enschede, THE NETHERLANDS; Improving Compatibility and Interaction of Polymers and Additives in Rubber by Surface Modification in a Plasma Polymerization Process
10:35-11:00: COFFEE BREAK
11:00-11:30: Gon Seo; School of Chemical Engineering, Chonnam National University, Gwangju 500-757, Korea; Improved Tensile and Dynamic Properties of SBR Compounds Reinforced with Networked Silicas Prepared Using Silanes as Connecting Materials firstname.lastname@example.org
11:30-12:00: A Babik and V. Cech; Institute of Materials Chemistry, Brno University of Technology, Purkynova 118, CZ-61200 Brno, CZECH REPUBLIC; Self-assembled Monolayers of Vinyltriethoxysilane and Vinyltrichlorosilane
12:00-12:30: Roy U. Rojas Wahl; Momentive Performance Materials, 769 Old Saw Mill River Road, Tarrytown, NY 10591; The Reaction Between Organoalkoxysilane Esters And 1,3-Diols To Form Cyclic Silane Esters
SILANES IN ADHESION AND BONDING
2:00-2:30: A. N. Rider and N. Brack; DSTO, Melbourne, AUSTRALIA; The Influence of Surface Roughening and Plasma Treatment on the Environmental Resistance of Epoxy to Titanium Adhesive Bonds email@example.com
2:30-3:00: E.H.N. Pow K.K.C. Yeung and J.P. Matinlinna; Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong, HONG KONG; HEMA and Silane Blend Effects on Resin-Titanium Bonding firstname.lastname@example.org
3:00-3:30: L. Hoferek, E. Palesch and
V. Cech; Institute of Materials Chemistry, Brno University of Technology, Purkynova 118, CZ-61200 Brno, CZECH REPUBLIC; Plasma-polymerized Films Based on Tetravinylsilane Monomer
3:00-4:00: COFFEE BREAK
4:00-4:30: Hari T Deo; Institute of Chemical Technology Deemed University, Mumbai, INDIA; The Enhanced Interfacial Adhesion Phenomena Using Ti-based Polymeric Surface-modifying Formulations email@example.com
4:30-5:00: Tsutomu Furuta and Akira Nakajima; Department of Metallurgy & Ceramics Science, Graduate School of Science & Technology, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552, JAPAN; Evaporation and Sliding of Water Droplets on Fluoroalkylsilane Coatings with Nanoscale Heterogeneity firstname.lastname@example.org
5:00-5:30: M. Masudul. Hassan, Marco Mueller, Diana J. Tartakowska and Manfred H. Wagner; Department of Chemistry, M C College, National University, Sylhet-3100, BANGLADESH; Grafting of Gycidyl Methacrylate onto Isotactic Polypropylene Used as a Compatibiliser For Composite Preparation email@example.com
SILANE CHEMISTRY AND NANOSTRUCTURES
9:00-9:30: Jane Hollenberg, Yun mi Kim, Janis Matisons and Barry Arkles; Gelest Inc., 11 East Steel Road, Morrisville, PA 19067; Evaluating the Hydrolytic Stability of Silane, Titanate and Phosphate Coupling Agents on Metallic and Silicious Substrates firstname.lastname@example.org
9:30-10:00: Bhanu P. S. Chauhan, Leon Prasanth K, Ramani Thekkathu, Ankita Shah, Hardika Shukla, Vanessa Comerón and Tamar Lesnoy: Engineered Nanomaterials Laboratory, Department of Chemistry, William Paterson University, 300 Pompton Road, Wayne, NJ 07470-2103; Hydrosilanes as Coupling Agents for “Living” Metal Nanopartcles Surfaces
10:00-10:30: Guo Liang Li, K. G. Neoh and
E. T. Kang; Department of Chemical & Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260; Silane-Promoted Synthesis of Functional Hollow Polymeric and Hybrid Micro- and Nanostructures
10:30-11:00: L. Wang, C. Huang, E. T. Kang and K. G. Neoh; Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260; Designing Functionalized Magnetic Nanoparticles via Silane Anchors for Biomedical Applications email@example.com
Stephen Coulson; P2i Ltd., 127 North, Milton Park, OX14 4 SA, Abingdon, Oxfordshire, UK
Plasma Surface Modification for Increased Hydrophilicity
Modern consumer and industrial products are manufactured from a wide range of materials that are selected for specific bulk properties, cost effectiveness and/or look and feel. However, many of the manufacturing materials chosen in this way do not display the optimum surface properties. This presents a vast opportunity for surface modifications to display desirable properties such as hydrophilicity, hydrophobicity, and oleophobicity. It is critical that these modifications do not alter the bulk properties of the product, in order to retain desirable physical attributes. A novel, patented liquid-repellent technology, by P2i, can readily apply functional nano-coatings onto the surface of a wide variety of products made from a diverse range of materials. The process uses a pulsed plasma deposition process at low pressures and, importantly, this allows coating of complete 3D products/end devices. Regarding repellency, a coating can be produced that is 3 times more repellent to liquids than PTFE. By changing the chemistry of the process, a surface can be made very hydrophilic. Since this coating is well adhered to the substrate surface, it lends itself to improvements in adhesion. This technology is fully industrialised and is used in a number of market sectors.
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Mikko Tuominen1, Hannu Teisala1, Mikko Aromaa2, Milena Stepien3, Jyrki M. Mäkelä2, Jarkko J. Saarinen3, Martti Toivakka3 and Jurkka Kuusipalo1
1) Paper Converting and Packaging Technology, Tampere University of Technology,P.O.Box 541, FI-33101 Tampere, FINLAND
2) Aerosol Physics Laboratory, Tampere University of Technology,PO.Box 692, FI-33101 Tampere, FINLAND
3) Laboratory of Paper Coating and Converting, Center for Functional Materials, Åbo Akademi University, FI-20500 Turku, FINLAND
Generation and Stimulation of Liquid Flame Spray (LFS) Coating
Titanium dioxide (TiO2) and silicon dioxide (SiO2) nanocoatings were successfully deposited on-line at atmospheric conditions on paper, paperboard and low density polyethylene (LDPE) laminates using a thermal liquid flame spray (LFS) method. LFS-coatings possess high surface roughness, in micro- and nano-scale, and hence the superhydrophilic (<10̊) or superhydrophobic (>160̊) surfaces can be created. The superhydrophobic surfaces showed “sticky”, i.e. a high adhesion to water droplets, and “roll-off”, i.e. a low adhesion to water droplets, nature depending on the substrate and LFS parameters used.
Figure 1. The LFS coating process (on-line) and SEM images of the paper surface before (a & d), SiO2 coated (b & e) and TiO2 coated (c & f) paper surface.
TiO2 is a photoactive material, therefore the wettability of the TiO2 coating can be adjusted to any precise level from superhydrophilic to superhydrophobic. UV light, corona or atmospheric plasma treatment can used to decrease the CAW from >160̊ down to <10̊. The hydrophobicity of the TiO2 surface can be returned by heat treatment or plasma deposition. Furthermore, the conversion of TiO2 coating wettability can be done repeatedly.
Figure 2. The stimulation methods of LFS-TiO2 coated paperboard surface.
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Saswati Datta; Procter and Gamble , Miami Valley Innovation Center, 11810 East Miami River Road, Cincinnati OH 45252
"Skin Mimic": Surface Modification of Polymers to Mimic Human Skin Properties
(Abstract not available)
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Shubhra Gangopadhyay, Venu Korampally, Singdha Praharaj, Vamsi Mamidi, Bryant Harris, and Luis Polo Parada, University of Missouri, Columbia, MO
Sangho Bok and Keshab Gangopadhyay, NanosTechnologies, LLC, Columbia, MO
Polymethyl Silsesquioxane Nanoparticles, their Surface Modifications and Applications in Microsystems
We describe a method for the preparation of colloidal dispersions of 5 nm Polymethyl Silsesquioxane (PMSSQ) nanoparticles and their applications. The PMSSQ nanoparticle – polymer composites above the decomposition temperature of the polymer forms highly porous films composed of PMSSQ nanoparticles. Optically smooth and hydrophobic films with low refractive indices (as low as 1.048) and high surface areas (as high as 1325 m2/g) have been achieved with this approach. In addition, we describe a facile method to control the final nanostructure of these films through controlling the surface energy of the substrates thereby allowing spontaneous patterning of these films into regions of contrasting optical properties. The surface of the films has been modified using plasma to create carboxyl groups for biological sensor applications. The PMSSQ nanoparticles are also utilized as fillers for the preparation of sol-gel silica/PMSSQ nanoparticle composites. These composites are applied on glass, polymer and metal surfaces as hydrophobic, flexible, wear resistant, corrosion-resistant and adhesive coatings.
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N. De Geyter1, R. Morent1, T. Jacobs1, S. Van Vlierberghe2, P. Dubruel2, Christophe Leys1
1) Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering, Ghent University, Jozef Plateaustraat 22, 9000 Gent BELGIUM
2) Polymer Chemisty & Biomaterials Group, Department of Organic Chemistry, Ghent University, Krijgslaan 281 S4, 9000 Gent, BELGIUM
Medium Pressure Plasma Treatment of Biodegradable PLA and PCL
Polylactic acid (PLA) and polycaprolactone (PCL) are well-known biodegradable polymers and have been previously used for several biomedical applications such as bone fixation devices (plates, pins, screws, etc.) and as tissue engineering scaffolds. Although both polymers are known to be biocompatible and widely used in the field of medicine, they are often unsuitable to use due to its low wettability and low surface energy, leading to poor cell attachment and cell proliferation. As a result, surface modification of PLA and PCL is usually necessary to add additional functional groups, which can in turn be used to link peptide sequences to the surface. These short peptide sequences are recognized by cell membrane receptors leading to the promotion of cell attachment and spreading. In this work, a medium pressure dielectric barrier discharge (DBD) will be used to alter the surface properties of PLA and PCL. Results show that after plasma treatment, the surfaces become more hydrophilic, mainly due to the incorporation of oxygen at the surface. After plasma treatment, cell cultures are grown onto the surfaces to study the cell adhesion.
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Kerry A. Wilson1, Craig A. Finch1, Phillip Anderson1, James J. Hickman1 and Frank Vollmer2
1) NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando FL 32828, USA.
2) The Rowland Institute, Harvard University, 100 Edwin H. Land Blvd, Cambridge, MA 02142, USA.
Quantification and Structure Evaluation of Protein Adsorbed at Defined Interfaces and its Effect on Subsequent Cell Culture
We have constructed a whispering gallery mode (WGM) sensor system to monitor the adsorption of protein to alkysilane self-assembled monolayers (SAMs) at solution concentration levels where measurements were unattainable with other techniques. The adsorption of protein was quantified by monitoring the change in the optical resonance frequency of a silica microsphere as protein accreted to the functionalized sensor surface. The adsorption of dilute solutions (1 mg/ml or less) of fibronectin (FN) on alkylsilane SAMs was studied as a model system, and it was found that FN adsorbed at unexpectedly high and biologically relevant surface densities. Standard adsorption models were then fitted to the experimental data to interpret the kinetics observed. The protein adsorption results, which indicated that an amine containing surface and a fluorinated surface adsorbed the same amount of FN, were then tested by culturing neurons and myocytes on the surfaces., Cells thrived on the amine surface, but didn’t on the fluorinated modified surface. A PEG surface did not adsorb an appreciable amount of FN and did not support cell growth. The combination of WGM sensor measurements for protein adsorption quantitation, modeling, and cell culture studies allowed us to make determinations about the protein confirmation on the surface and its effect on cell survival. The high sensitivity and simplicity of the WGM biosensor, combined with its ability to quantify the adsorption of any dilute protein in a label-free assay, establishes the importance of this technology for biomaterial derivitization for implants and surfaces for cell culture.
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Shantanu Bhattacharya; Department of Mechanical Engineering, IIT Kanpur, INDIA
Plasma Modification of Polymer Surfaces and Their Utility in Building Biomedical Microdevices
Polymers are largely used in micro-systems where there may be biological detection and sensing and provide easier alternatives of fabrication for Biomedical Micro-devices. The most widely used polymeric system amenable to micro-fabrication is that of silicone rubber particularly poly dimethyl siloxane(PDMS).The principle advantage that silicone rubber offers is in terms of its ability to get replicated with high aspect ratios by micro-molding . Apart from this other polymer systems like resists or epoxies find extensive use in micro-fabrication providing many aspects like interlayer bonding, selective patterning, modified physical properties like variable electrical or optical properties etc. Most polymer systems are amenable to rapid change in their surface energies as they are exposed to gas plasmas or UV radiation. Such changes can sometimes be reversible and the exposed surfaces can regain their original configuration with time. In general the polymer surface after such external stimuli become highly dynamic in constitution and this makes them well suited to some prominent applications in realizing Biomedical micro-devices (BMMD). Our groups have extensively worked in the area of polymer surface modification by external stimuli and its characterization and through this paper we have attempted to review some of the groups work.
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X. F. Hu, F. Zhang, E. T. Kang and K. G. Neoh; Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260
Exploiting Surface Chemical Modification of Natural Biopolymers for Selective Bio-interactivity with Bacteria and Bone Cells in Orthopedic Applications
Orthopedic implants suffer occasional failures as a result of biomaterial-centered infection and/or poor bonding of the implant to bone tissue. Upon insertion, the implant presents a surface for colonization by both the host tissue cells and bacteria which may be present. In the competition for colonization of the implant surface, the probability of successful tissue integration would be greatly enhanced if tissue integration occurs before appreciable bacterial adhesion can take place since once bacterial adhesion has occurred, it is unlikely that tissue cells will be able to displace these primary colonizers. Infection in orthopedic implant surgery remains one of the most dreaded and major complications in orthopedic practice despite the use of modern antibiotic regimes and surgical measures. In this work, we report on the use of two natural biopolymers, silk sericin and chitosan, for tailoring titanium implant surfaces to inhibit bacteria adhesion and simultaneously promote osteoblast functions. In the first approach, titanium surfaces were modified with poly(methacrylic acid) followed by immobilization of silk sericin. The methacrylic acid brushes from surface initiated atom transfer radical polymerization significantly reduce the adhesion of the two bacterial strains (Staphylococcus aureus and Staphylococcus epidermidis) tested. At the same time, the immobilized sericin promotes osteoblast adhesion, proliferation, and alkaline phosphatase activity (ALP). In the second approach, the titanium substrates were functionalized with chitosan or carboxymethylated chitosan (CMCS) either via covalent grafting or electrostatic interactions. The chitosan was further conjugated with biomolecules such as peptides or growth factors to enhance osteoblast functions. Bacterial adhesion on these functionalized surfaces was significantly decreased compared to that on the pristine substrates while osteoblast spreading, ALP activity, and calcium mineral deposition were concomitantly enhanced. Such bio-interactive surfaces with these dual functionalities are promising for orthopedic applications.
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K. Fricke1, K. Duske2, A. Quade1, B. Nebe2, K. Schröder1, Th. v. Woedtke1
1) Leibniz Institute for Plasma Science and Technology (INP Greifswald e.V.), Greifswald, GERMANY
2) University of Rostock, Biomedical Research Center, Dept. of Cell Biology, Rostock, GERMANY
Comparison of Low-temperature Plasma Processes on the Surface Properties of Polystyrene and Their Impact on the Growth of Osteoblastic Cells
Low-temperature plasmas such as low-pressure plasma and atmospheric pressure plasma are the widely used industrial technologies for the modification of heat sensitive surfaces. Plasma-induced functionalization processes are applied to create chemical functional groups at the substrate surface which consequently influence the wettability, the cell attachment, and the cell growth. For instance, it is well known that a high amino group density at the surface improves the cell adhesion .
In the present study the behaviour of human osteoblastic cells (MG-63) with respect to cell growth and spreading on different polystyrene surfaces is investigated. A comparison is made between plasma-functionalized polystyrene and commercial available polystyrene – such as tissue culture PS (TC PS) and PrimariaTM. In particular, the polystyrene surfaces were exposed to different low-temperature plasma processes including: 1. surface coating with a thin film of microwave plasma polymerized allylamine (PPAAm), 2. exposure to ammonia-containing plasma 3. treatment of polystyrene with low-pressure oxygen plasma, and 4. treatment with argon/oxygen plasma using an atmospheric pressure plasma jet. The cell studies were accompanied by surface analysis comprising X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).
 K. Schröder, B. Finke, H. Jesswein, F. Lüthen, A. Diener, R. Ihrke, A. Ohl, K.-D. Weltman, J. Rychly and J.B. Nebe, J. Adhesion Sci. Technol. 24, 905 (2010)
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Bret Chisholm, Partha Majumdar, Shane Stafslien, and David Christianson;
Center for Nanoscale Science and Engineering, North Dakota State University
Fargo, ND, USA
An Investigation of Antimicrobial Coatings Derived from Quaternary Ammonium-Functional Alkoxysilanes Using Combinatorial/High-Throughput Methods
An extensive combinatorial/high-throughput workflow was used to construct detailed structure-property relationships for moisture-curable polysiloxane coatings derived from alkoxysilanes possessing quaternary ammonium salt (QAS) moieties. An array of QAS-functional alkoxysilanes were produced that possessed systematic variations in chemical structure. These QAS-functional alkoxysilanes were subsequently used to produce approximately 200 unique polysiloxane coatings and the antimicrobial properties characterized using high-throughput biological assays. Antimicrobial properties of the coatings were found to depend strongly the chemical structure of QAS-functional alkoxysilane. In addition to being dependent on QAS-functional alkoxysilane composition, antimicrobial properties were found to be dependent on silanol-terminated polysiloxane molecular weight. Surface characterization of the coatings indicated that relationships between antimicrobial activity and chemical structure of the QAS-functional alkoxysilane was primarily driven by the process of self-assembly of QAS groups at the coating/air interface as opposed to the inherent antimicrobial activity of the QAS-functional alkoxysilanes. From the data obtained, a relatively narrow region of the compositional space was identified that resulted in the production of coatings with broad-spectrum antimicrobial activity. These coatings may have utility for combating both device-related infection in the healthcare industry and marine biofouling in the shipping industry.
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A. Ansarifar; Materials Department, Loughborough University, Leicestershire LE11 3TU, UK
How a Sulfur-Bearing Bifunctional Organosilane Changed the Shape of Rubber Formulation
Rubber compounds contain up to eight classes of rubber chemicals. The cure system consists of primary and secondary accelerators, primary and secondary activators and elemental sulfur. Excessive use of the curing chemicals is harmful to health, safety and the environment and their use is restricted by the new European chemicals policy, Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). Reduction in the use of these chemicals is now a priority.
Some unsaturated hydrocarbon rubbers were cured and reinforced with different amounts of a precipitated silica the surfaces of which were pre-treated with bis(3-triethoxysilylpropyl) tetrasulfide (TESPT). TESPT is a sulfur-bearing bifunctional organosilane which chemically bonds silica to the rubber. The chemical bonding between the filler and rubber was optimized via the tetrasulfane groups of TESPT. The crosslink density changes were measured as a function of the loading of the chemical curatives.
It emerged that the requirement for the curatives depended on the composition of the rubber and the loading of the filler. This reduced the curatives and simplified the cure system. Major benefits were also gained for health, safety and the environment.
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W. Dierkes1, M. Tiwari1, R. Datta1, A. Talma1, J. Noordermeer1 and W. van Ooij2
1) University Twente, Faculty of Engineering Technology, Department of Elastomer Technology & Engineering, Enschede, THE NETHERLANDS
2) Department of Chemical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA
Improving Compatibility and Interaction of Polymers and Additives in Rubber by Surface Modification in a Plasma Polymerization Process
Blending of elastomers and additives is still a challenge in rubber compounding as the thermodynamic compatibility of polymers in a blend is rather low, and the various components differ significantly in polarity and reactivity. As the quality of rubber strongly depends on morphological properties, an improvement of the compatibility of the compound components allows improving the property profile of the material.
Surface treatment by a plasma polymer coating allows tailoring the surface polarity and chemistry of additives while maintaining the structure, a crucial factor in the case of fillers. A study on the effect of different monomers for the surface coating of carbon black, silica, sulphur and CBS was done in straight polymers as well as in dissimilar blends. The dispersion and distribution of the additives in the polymer matrix as well as the influence on the morphology of polymer blends were investigated, next to the influence on mechanical properties.
Silica was found to be easily coated by different types of monomers compared to carbon black and curing additives. The effect of plasma-treatment of the additives on the morphological and mechanical properties of the material was varying with the chemical structure of the surface coating, allowing tailoring the additive-polymer interaction according to the requirements.
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Gon Seo; School of Chemical Engineering, Chonnam National University, Gwangju 500-757, Korea (South)
Improved Tensile and Dynamic Properties of SBR Compounds Reinforced with Networked Silicas Prepared Using Silanes as Connecting Materials
The dynamic property of tread rubber compounds becomes an important issue to be urgently improved for manufacturing environmentally-friendly tires with better wet traction and lower rolling resistance in order to enhance their safety and fuel efficiency. Networked silicas with three-dimensional networks among silica particles have been prepared by using various silanes as connecting materials. The networked silica considerably improves the tensile property of rubber compounds by increasing the entanglement of rubber molecules with the connecting materials rather than the chemical bonds formed between silica particles and rubber molecules as in the conventional rubber compounds reinforced with silica and coupling reagent. The rubber compounds reinforced by the networked silicas also exhibit improved dynamic properties deduced from their tan delta curves. The absence of the chemical bonds between rubber molecules and silica particles lowers the restriction on the molecular deformation of rubber, improving wet traction. The entanglement in networked silica-filled rubber compounds lowers their hysteresis, resulting in lower rolling resistance. Furthermore, no emission of ethanol due to the elimination of conventional coupling reagents guarantees cleaner working atmosphere. The structure, dispersion, and surface property of the networked silicas and the performance of SBR compounds reinforced with them in terms of viscous, cure, tensile, dynamic, and abrasive properties will be discussed in this presentation.
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A Babik and V. Cech; Institute of Materials Chemistry, Brno University of Technology, Purkynova 118, CZ-61200 Brno, CZECH REPUBLIC
Self-assembled Monolayers of Vinyltriethoxysilane and Vinyltrichlorosilane
Although a molecular monolayer is only a few nanometers thick, it can completely change the chemical and physical properties of a surface. Molecular monolayers can be readily prepared using chemisorptions on a variety of surfaces. The self-assembled monolayers (SAMs) are highly ordered two-dimensional structures that form spontaneously by the immersion of an appropriate substrate into a solution of an active surfactant in an organic solvent. The most common adsorbate/substrate combinations are alkylsilanes on oxide surfaces. Our study is aimed at SAM deposition using vinyltriethoxysilane (VTES) or vinyltrichlorosilane (VTCS) molecules chemisorbed on silicon oxide surfaces. The kinetics of formation of VTES or VTCS monolayers on planar glass substrate or silicon wafer with native silicon dioxide layer was characterized by contact angle measurements. The surface free energy and its components were evaluated using the Owens-Wendt-Kaelble geometric mean method and the Wu harmonic mean method. Spectroscopic ellipsometry was used to determine the thickness of deposited films. Detailed information on the elemental composition of SAMs was obtained by X-ray photoelectron spectroscopy (XPS). Surface morphology of deposited films was investigated by atomic force microscopy (AFM).
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Roy U. Rojas Wahl; Program Leader, Polymer Additives Silanes, Momentive Performance Materials, 769 Old Saw Mill River Road , Tarrytown, NY 10591, U.S.A.
The Reaction Between Organoalkoxysilane Esters And 1,3-Diols To Form Cyclic Silane Esters
Organoalkoxysilane esters are well known coupling agents and crosslinkers.
Typically, they are converted to reactive silanols by hydrolysis, which is often
accompanied by release of undesired volatile organic compounds (VOCs). Here we describe certain aspects of transesterification reactions of 1,3-diols with conventional silanes as a means to yield products that can help lower VOCs. Mechanistic insights along with suggested applications will be discussed.
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A. N. Rider1 and N. Brack2
1. DSTO, Melbourne, AUSTRALIA
2. La Trobe University, Melbourne, AUSTRALIA
The Influence of Surface Roughening and Plasma Treatment on the Environmental Resistance of Epoxy to Titanium Adhesive Bonds
Titanium alloy was roughened using either abrasion techniques or grit-blasting with 50 micron alumina particles. The environmental resistance of the bonds formed between a rubber toughened epoxy adhesive and the titanium alloy was significantly influenced by the degree of surface roughness. Further, the addition of a thin organosilane film and primer to the titanium, significantly increased the environmental resistance of the adhesive bond. An atmospheric plasma treatment of the titanium prior to organosilane treatment also improved uniformity of the resultant thin film as determined by AFM and XPS. Characterisation of the titanium surfaces before bonding and after testing revealed some abrasive particles can be left embedded in the titanium surface. Under mode I stress and a hygrothermal environment the particles may pull-out from the titanium surface, which leads to a bond with lowered fracture toughness. The chemical composition of the abrasive particles may be related to their adhesion to the titanium substrate.
RETURN TO SESSION IV
E.H.N. Pow1* K.K.C. Yeung1, J.P. Matinlinna2
1) Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong, HONG KONG
2) Dental Materials Science, Faculty of Dentistry, The University of Hong Kong, HONG KONG
*corresponding author, firstname.lastname@example.org
HEMA and Silane Blend Effects on Resin Titanium Bonding
Objectives: To evaluate the adhesive performance of two activated organofunctional silane coupling agents alone and two silane blend systems with HEMA as adhesion promoters for bonding an experimental bis-GMA to a silica-coated titanium surface, under 3 different storage conditions.
Materials and methods: 1) 3-methacryloxypropyltrimethoxysilane, 2) 3-acryloxypropyltrimethoxysilane, 3) a silane blend consisting of 3-methacryloxypropyltrimethoxysilane with 0.5% vol. HEMA, 4) a silane blend consisting of acryloxypropyltrimethoxysilane with 0.5% vol. A commercial 3-methcryloxypropyltrimethoxxysilane (EPSE SilTM) was used as a control. The silanes were applied onto tribochemically silica-coated titanium surfaces (Rocatec®). Experimental bis-GMA resin stubs were applied and photo-polymerized onto titanium. The specimens were stored in three different conditions: 1) dry storage for 24 hours, 2) storage in de-ionized water at 37C for six months and 3) de-ionized water at 37C with regular thermocycling interval (6000 cycles, 5-55C) for 6 months, respectively. Shear bond strengths of the resin to titanium were measured by using a universal testing machine. The surface examination, after shear bond strength test, was made with a scanning electron microscope (SEM).
Results: Highest shear bond was obtained with 3-acryloxypropyltrimethoxysilane stored in dry for 24 hours (20.2+3.2MPa), and the lowest result was obtained with 3-methcryloyoxypropyltrimethoxxysilane (EPSE SilTM) in de-ionized water at 37C with regular thermocycling interval (6000 cycles, 5-55C) for 6 months (1.4+0.6MPa). The type of storage condition and type of failure mode affected significantly the shear bond strength (p<0.05). The shear bond obtained from dry storage was highest, while the shear bond obtained from thermocycled storage was lowest. Adhesive failure was the main failure mode with 87.2% of all specimens. The use of HEMA did not significantly affect the shear bond strengths.
Conclusion: The use of HEMA does not improve the adhesive performance of the experimental resin to titanium.
Matinlinna JP, Lassila LVJ, Vallittu PK. Experimental Novel Silane System in Adhesion Promotion between Dental Resin and Pretreated Titanium. Silicon 2009; 1(4):249-254
Puska M, Lassila L, Seppälä J, Vallittu P, Matinlinna J. Effect of pH and alcohol solvent on bonding Bis-GMA/MMA resin onto silica-coated and silanized titanium. J Adhes Sci Techn 2009; 23: 991-1006.
Matinlinna JP, Lassila LVJ, Vallittu PK. The Effect of Five Silane Coupling Agents on the Bond Strength of a Luting Cement to a Silica-coated Titanium. Dent Mater 2007; 23:1173-1180.
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L. Hoferek, E. Palesch and V. Cech; Institute of Materials Chemistry, Brno University of Technology, Purkynova 118, CZ-61200 Brno, CZECH REPUBLIC
Plasma-polymerized Films Based on Tetravinylsilane Monomer
Plasma-polymerized organosilicones constitute a class of materials with a rich and varied scientific background. This class of materials possesses a special characteristic, which distinguishes it from other plasma polymers – the ability to vary and control the degree of its organic/inorganic character (i.e., the carbon content) and the polymer cross-linking by the appropriate choice of fabrication variables. This allows one to control many physico-chemical properties over wide ranges resulting in an extraordinary potential for useful applications, which are only now beginning to be tapped. The organosilicon plasma polymers are widely recognized for their potential in optical, mechanical, and electronic applications. Mostly hard coatings are developed as protective layers, but we aimed at soft coatings using pulsed plasma. A reduction of plasma energy (power), but operated in several orders of magnitude, enabled us to control chemical composition and structure of plasma polymer coatings resulting in a wide range of mechanical, optical, and surface properties.
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H. T. Deo; Institute of Chemical Technology Deemed University, Matunga, MUMBAI - 400077, INDIA.
Present Address (While in USA): 1909 Waverly CT, APT 5, COLUMBIA, MO 65201-5493.
The Enhanced Inter-facial Adhesion Phenomena Using Ti - Based Polymeric Surface-modifying Formulations
Adhesive polymers/specialty chemicals are being extensively used for surface modifications of raw materials and formulations consumed worldwide. They are based on Selene or other eco-friendly performance materials. Any additive/modifier has to promote Green Technology. In this paper, we are presenting results of our research aimed at achieving, in a small way, these objectives in the field of surface modification of steel and cement employed in concrete formulations. Such Green Concretes can be useful in civil engineering constructions of houses, highways, air-ports, ports, dams, canals, railways, reactors including atomic reactors, etc. This Paper shows that, by incorporating small quantities of specially synthesized Titanium-based specialty formulations – Pureze-TS-01 (PTS) and Pureze-TC-03 (PTC), a significant surface modification of steel and cement particles and their aggregates was achieved. PTS molecules offer strong chemical interaction with molecules of metal-surface exhibiting improved corrosion protection due to favorable combination of its barrier properties. Its unique formulation enables removal or formation of rust layers on metal surface making it fully rustproof even under the most hostile environment. This results in near 100% surface availability for interaction and adhesion in the concrete. Further, by incorporating just 0.1% PTC (W/W), strength of the resultant concrete almost doubled. Alternatively, about 30% saving in cement consumption could be possible for a given strength. These findings are attributed to the possible enhancement of inter-particle as well as inter-material adhesion to a substantially higher extent. The Paper describes achievements of substantial savings, superior surface performance, and protection and improvement of environment.
(Abstract submitted for presentation of the Paper at Eighth International Symposia of MST to be held in June 2011 at Danbury, Connecticut, USA)
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Tsutomu Furuta and Akira Nakajima; Department of Metallurgy & Ceramics Science, Graduate School of Science & Technology, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552, JAPAN
Evaporation and Sliding of Water Droplets on Fluoroalkylsilane Coatings with Nanoscale Heterogeneity
Evaporation and sliding behaviors of water droplets were investigated on smooth and rough fluoroalkylsilane coatings. The rough coating possesses nanoscale roughness and chemical heterogeneity on its surface. Evaporation behaviors for these two coatings differed when nanoliter-scale droplets were used, although they were nearly identical for microliter-scale droplets. The droplets on the smooth coating exhibit greater sliding acceleration and a larger slipping velocity ratio than those on the rough coating. Both the evaporation behavior of nanoliter-scale droplets and sliding velocity of microliter-scale droplets were affected by nanoscale surface heterogeneity. They are indicators for highly homogeneous smooth silane coatings.
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M. Masudul. Hassan1, Marco Mueller2, Diana J. Tartakowska2 and Manfred H. Wagner2
1) Department of Chemistry, M C College, National University, Sylhet-3100, BANGLADESH
2) Technical University of Berlin, Institute of Material Science and Technology, Chair of Polymer Engineering/Polymer Physics, D-10623 Berlin, GERMANY
Grafting of Gycidyl Methacrylate on to Isotactic Polypropylene Used as a Compatibiliser For Composite Preparation
Gycidyl methacrylate grafted isotactic polypropylene (GMA-g-PP) copolymer have been manufactured by free radical polymerization using benzoyl peroxide (BPO) initiator with twin screw extruder. FTIR, DSC and SEM result corroborated the evidenced of the modification of the PP surface. GMA-g-PP is more hydrophilic than unmodified polypropylene (PP). Thus, this method can be used to obtain physico-chemically altered PP surfaces. Moreover, the modified PP matrix i.e. GMA-g-PP can be used as a compatibiliser to prepare composites with enhanced properties.
Corresponding to: M. Masudul Hassan (e-mail: email@example.com)
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Jane Hollenberg, Yun mi Kim, Janis Matisons, Barry Arkles; Gelest Inc., 11 East Steel Road, Morrisville, PA 19067, USA
Evaluating the Hydrolytic Stability of Silane, Titanate and Phosphate Coupling Agents on Metallic and Silicious Substrates
Much has been written about silanes, titanates and phosphates as surface modifying agents. These materials are used to provide hydrophobic properties on various substrates. Data on the comparative performance of hydrocarbon substituted analogs of all three classes of these surface modifying agents on various substrates is generally not available. We examined three commonly used octadecyl (C18) substituted materials, octadecyltrimethoxysilane, (Catalogue No. SIO6645.0), titanium triisostearoylisopropoxide (Catalogue No. AKT887.5), and octadecylphosphonic acid (Catalogue No. OMPH062) and evaluated their hydrolytic stability on three metallic substrates (zirconium, titanium, and carbon steel) as well as two siliceous substrates, (borosilicate and quartz glasses). Each substrate was exposed to four different aqueous solutions: deionized. water at room temperature; deionized water at 80C; 1N acetic acid solution, and 1N NH4OH solution for set time periods. The hydrolytic durability of the applied coupling agents was monitored by the change of contact angle on the substrates (after extended exposure to deionized water. This study provides invaluable information on selecting not only the best surface modifying agent, but also provides optimum application conditions on a variety of key substrates.
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Bhanu P. S. Chauhan, Leon Prasanth K, Ramani Thekkathu, Ankita Shah, Hardika Shukla, Vanessa Comerón and Tamar Lesnoy: Engineered Nanomaterials Laboratory, Department of Chemistry, William Paterson University, 300 Pompton Road, Wayne, NJ 07470-2103
Hydrosilanes as coupling agents for “Living” Metal Nanopartcles Surfaces
Transition metal nanoparticles have become one of the very important classes of nanosized materials because of their unique properties resulting due to size and shape confinement. We have been investigating the synthesis, characterization and property profiling of transitional metal nanoparticles for quite some time now and have devised very unique ways to stabilize and utilize such nanoparticles in applications ranging from catalysis, to selective drug delivery.1-3 This quest has pointed us to investigate the surface chemistry of transition metal nanoparticles as it relates to their catalytic activity, selectivity and recyclability properties.
In this presentation, we will present our recent work3 on the coupling chemistry of nanoparticles of Ag, Au, Pd, Pt, Rh and Ru metals with various types of silanes. In our method these particles are generated via hydrosilane induced reduction of corresponding metal salts. This strategy provides a simple, one step room temperature access to stable, analyzable and utilizable metals nanoparticles in good yields. Though, the questions such as optimum stability vs optimum activity and selectivity need more investigations but our recent results show that the interaction of residual Si-H bonds with nanoparticle surface plays a very important role in this chemistry. We will also present the aspect related to their living nature and their utility in the fields such as catalysis.
1. Auerbach, A. ; Chauhan, B. P. S.; Clarke, R.P.; Haider, I. M.; Latif, U. US Patent; 2010 (08/2010), No. US 7,745,547B-1
2. Chauhan, B. P. S.; Rathore, J. S. J. Am. Chem. Soc. 2005, 127, 5790-5791.
3. Chauhan, B.P.S.; Sardar, R. Macromolecules 2004, 37, 5136-5139.
4. Chauhan, B. P. S.; Thekkathu, R.; Leon, P. K.; Mandal, M. and Lewis, k. Appl. Organometal. Chem. 2010, 24, 222-228.
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Guo Liang Li, K. G. Neoh and E. T. Kang; Department of Chemical & Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260
Silane-Promoted Synthesis of Functional Hollow Polymeric and Hybrid Micro- and Nanostructures
Combination of sol-gel reaction with distillation-precipitation polymerization, controlled radical polymerization (atom transfer radical polymerization or ATRP) and/or ‘click’ reactions (alkyne-azide and thiol-ene ‘click’ chemistry) allows the design and synthesis of a wide-range of functional hollow polymeric, inorganic and polymer-inorganic hybrid micro- and nanostructures. These micro- and nanostructures include stimuli-responsive and functional (i) hollow polymeric microspheres and concentric hollow silica microspheres, (ii) double-walled concentric hollow polymeric microspheres, (iii) concentric hollow nanospheres of mesoporous silica shell-titania core, (iv) core-double shell microspheres, (v) hybrid nanorattles of catalytic metal core and polymer shell, (vi) hairy hollow microspheres of fluorescent shell and polymer brushes, (vii) binary polymer brushes on silica@polymer hybrid nanospheres and hollow polymer nanospheres, and (viii) hairy hybrid microrattles of metal nanocore with functional polymer shell and brushes.
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L. Wang, C. Huang, E. T. Kang and K. G. Neoh; Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260
Designing Functionalized Magnetic Nanoparticles via Silane Anchors for Biomedical Applications
There is increasing interest in recent years in using superparamagnetic iron oxide nanoparticles (SPIONs) for biomedical applications such as magnetic resonance imaging (MRI) contrast enhancement, drug delivery and hyperthermia. However, designing these nanoparticles for use in a biological environment can be rather challenging. Due to the high surface area to volume ratio of these nanoparticles, there is a tendency for aggregation. Furthermore, in tumor targeting applications, these nanoparticles have to evade the body’s immune system and selectively accumulate in the tumor. In this work, we report on two strategies to modify the SPIONs with the a hydrophilic polymer shell with a cancer targeting ligand (folic acid) to achieve targeting of tumor cells while minimizing uptake by macrophages. Both strategies rely on the use of silane as the surface anchor on the SPIONs. In the first strategy, an atom transfer radical polymerization (ATRP) initiator was synthesized via the reaction of γ-aminopropyl triethoxysilane with 2-bromoisobutyryl bromide, and immobilized on the SPIONs surface. Surface-initiated ATRP of glycidyl methacrylate on SPIONs and subsequent reaction with ethylenediamine were carried out. This polymer coating renders the nanoparticles water-soluble, and at the same time generates functional groups for conjugation with folic acid. In the second strategy, nanoparticles of Fe3O4 core with fluorescent SiO2 shell were synthesized and grafted with hyperbranched polyglycerol. The numerous surface hydroxyl groups of these nanoparticles were conjugated with folic acid by a thiol ‘click’ reaction. The nanoparticles prepared by these two strategies have low cytotoxicity and favorable MR properties, and exhibit selective targeting of tumor cells while concomitantly the uptake by macrophages and normal cells is minimized.
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