Research Group Members

Senior Research Associate

Giles Dillingham, Ph. D. rdilling@uceng.uc.edu

Adhesive bonding of composite materials
    A lack of understanding of the factors involved in obtaining strong and durable adhesive bonds to composite materials prevents more widespread use of this technology in aircraft and automobile construction. Current technology uses abrasive blasting to clean and roughen the composite substrate. We are studying the relationship between abrasive blasting parameters, the resulting substrate chemistry and morphology (as well as sub-surface damage), and adhesive bond performance. We are developing extremely effective alternative surface preparation processes based on these studies.

Ultra-thin primers for promoting adhesion of thermoplastics to mineral surfaces in injection molding processes
    Gaskets for sealing automotive glass to autobodies is typically injection molded onto glass to which an adhesive has been applied in a previous step. Invisibly thin primers are preferable to thick adhesives for aesthetic reasons...the risk of cosmetic damage through mis-application is greatly reduced. In an injection molding process, however, a combination of low interfacial temperature and migration of plasticizers and other additives makes adhesion difficult to obtain. We are developing novel primer chemistries and thermoplastic compounds to provide excellent adhesion in an injection molding cycle.

Structure/property relationships in functional plasma-polymerized coatings
    Plasma polymers as coatings for surface engineering of materials can be structurally and functionally engineered on a submicron scale to optimize properties such as adhesion to the substrate, barrier properties and scratch resistance, surface energetics, and specific surface reactive functionality for properties such as adhesion. We are developing a thorough understanding of the relationship between substrate composition and morphology, plasma composition, and the structure and properties of the resulting coatings for applications such as corrosion-resistant primers for metals and scratch-resistant coatings for plastics.

Recent publications

1. “The Adhesion of Isocyanate-based Polymers to Steel”, R.G. Dillingham and C.J. Moriarty, accepted for publication in The Journal of Adhesion, 2002.
2. “Priming to Improve Adhesion”, Chapter 14 in Comprehensive Adhesion Science, Volume II: Surface Science of Adhesion, A. Pocius, M.K. Chaudhury, eds., Elsevier, 2002 (in press).
3. "Effect of Pretreatment on Chemical Structure and Corrosion Protection of Plasma-Polymerized Acetylene Films on Aluminum and Steel", E. Labonne, F.J. Boerio and R.G. Dillingham, Proc. 24th Annual Meeting of the Adhesion Society, The Adhesion Society, Inc., J. Emerson, ed., The Adhesion Society, Blacksburg, VA, 2001.
4. "Cohesive Zone Models of Polyimide/Auminum Interphases", K. M. Liechti , A. Shirani, R.G. Dillingham, F. J. Boerio, and S. M. Weaver, Journal of Adhesion v 73 n 2-3 2000 p.259-297.
5. "Ultra-Pure Cleaning and Surface Engineering of Metals, Glasses, Ceramics, and Polymers through Plasma Processes", R.G. Dillingham, Proc. International Cleaning Technology Exhibition, May 18-20, 1999, Rosemont, IL, pg. 305.
6. "Effect of Plasma Polymer Structure on Adhesive Joint Strength and Durability”, R.G. Dillingham, F.J. Boerio, Invited, Proc. 22nd Annual Meeting of the Adhesion Society, The Adhesion Society, Inc., D.R. Speth, ed., The Adhesion Society, Blacksburg, VA, 1999.

• Jennifer Chase chaseje@email.uc.edu

Developing low surface energy coatings for elastomeric materials using plasma polymerization of a fluorocarbon film. Also, engineering and chemically functionalizing a scaffold of carbon nanotubes for supporting lipid bilayers for selective molecular transport.

• Pablo Rosales rosalepi@email.uc.edu

Understanding and characterizing the interface between cold-rolled steel and plasma polymerized acetylene films for bonding to rubber, using the in-situ IR and XPS plasma reactors.

• Supa Wirasate wirasas@email.uc.edu

Understanding surface modification of polymers, such as polycarbonate and poly(tetrafluoroethane), through plasma treatment to improve scratch resistance and other material properties.

• Basak Benju bbengu@yahoo.com

Developing primers for in-mold adhesion of PVC to glass. Also, studying surface engineering of Al using plasma processing. A dual mode plasma reactor is used to deposit silica-like plasma polymerized films onto aluminum substrates using HMDSO, HMDSZ and TEOS as monomers and oxygen as a co-reactant. Determining the effect of processing variables and characterizing the films by surface analytical techniques such as VASE, RAIR, XPS, AFM, SEM and EIS.

• Munish Gupta munish78@hotmail.com

Understanding plasma polymerized hexamethyldisiloxane (HMDSO) and other silica-like films as primers for the adhesive bonding and inhibiting corrosion of aluminum. Microwave and radio frequency reactors are used for coating the aluminum. Various surface analysis techniques, such as ellipsometry, X-ray photoelectron spectroscopy (XPS), reflection absorption infrared spectroscopy (RAIR) and scanning electron microscopy (SEM) are used to characterize the substrates and films.

• Payal Kaul kaulpl@email.uc.edu

Understanding scratch resistance of polymers and relating scratch resistance to other material and chemical properties.

• Madhusmita Trasi trasim@email.uc.edu

Studying the effect of plasma power, pressure and deposition-time on the performance of plasma-polymerized acetylene (PPA) films in a rubber bonding environment. Plasma polymerization is an environmentally benign process to improve rubber to metal bonding, as opposed to the brass-plating techniques currently used. PPA films deposited on polished, cold-rolled steel serve as an effective primer for rubber-metal bonding. These films closely mimic the structure of unvulcanized rubber and therefore form a rubber-like network during the vulcanization process.

• Vijay Wagh vijaywagh@yahoo.com

Adhesive bonding of aluminum substrates aided by plasma polymerized primer films; testing for mechanical strength and durability.