Plasma Polymerization: A Novel, Environmentally-Compatible Process for Surface Engineering of Metals

EPA Grant Number: R829579
Title: Plasma Polymerization: A Novel, Environmentally-Compatible Process for Surface Engineering of Metals
Investigators: Boerio, F. James
Current Investigators: Boerio, F. James , Bengu, B. , Gupta, M.
Institution: University of Cincinnati
EPA Project Officer: Richards, April
Project Period: March 11, 2002 through March 10, 2006
Project Amount: $300,000
RFA: Technology for a Sustainable Environment (2001) RFA Text |  Recipients Lists
Research Category: Nanotechnology , Sustainability , Pollution Prevention/Sustainable Development


The goal of this project is to develop plasma polymerization as a novel, environmentally compatible process for depositing thin, corrosion-resistant primer films onto metals such as aluminum prior to structural adhesive bonding. Specific objectives include relating the composition of a plasma to processing variables such as power and pressure and to the structure and properties of films deposited from the plasma. Additional objectives include developing new plasma processes for engineering the surface of aluminum before the deposition of plasma polymerized films and characterizing the effluents from the plasma reactor.

Plasma polymerization is a process in which active species such as ions and free radicals are formed in a low pressure gas or plasma of a "monomer" by collisions between free electrons and monomer molecules when an electric field is applied to the gas. The active species react with themselves or with monomers to form polymer coatings on the surfaces of solids that are exposed to the plasma. Plasma polymerization is an extremely attractive process for pretreatment of metals. It enables a substrate to be cleaned and coated in the same reactor, without exposure to airborne contaminants, and it allows the synthesis and deposition of a coating material to be combined into one efficient step. The properties of a coating can be engineered for specific applications by varying appropriate process parameters during deposition and there are no liquid wastes that must be disposed of since plasma polymerization is a gas phase process.


The experimental approach will involve determining relationships between processing variables used to deposit plasma polymerized films on aluminum substrates, the composition of the plasmas, the molecular structure of the films, and the performance of the films as primers for structural adhesive bonding. Optical emission spectroscopy (OES) will be used to determine the composition of plasmas as a function of processing variables. Surface analysis techniques such as X-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIR), ellipsometry, scanning electron microscopy (SEM), and atomic force microscopy (AFM) will be used to determine the effect of processing variables on the molecular structure and morphology of the films. Electrochemical impedance spectroscopy (EIS), attenuated total reflection (ATR) infrared spectroscopy, fracture mechanics tests, and industrial test methods will be used to determine performance characteristics of the films, including the corrosion protection they impart to metal substrates, the rate at which penetrants such as water diffuse through the films, the interfacial fracture energy of films deposited on metal substrates, and the properties of the films as primers for structural adhesive bonding. Residual gas analysis (RGA) will be used to identify species present in the effluent from the reactor.

Expected Results:

Results of the project will include novel plasma processes for surface engineering metals such as aluminum prior to structural adhesive bonding and a related reduction at the source in the amount of liquid wastes, including chromate compounds, which enter the nation's waste stream each year due to metal pretreatment operations. Although the main emphasis in this project will be surface engineering of aluminum prior to adhesive bonding, the results will also apply to painting of aluminum. Considering the scale on which surface pretreatment of metals such as aluminum is carried out in the automobile and aircraft industries prior to structural adhesive bonding and painting operations, it is evident that these new processes will result in a significant impact on the nation's waste management responsibility by eliminating chromate compounds and other liquid wastes at the source.

Publications and Presentations:

Publications have been submitted on this project: View all 9 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 1 journal articles for this project

Supplemental Keywords:

waste reduction, clean technologies, transportation, plasma polymerization., RFA, Scientific Discipline, Sustainable Industry/Business, Chemical Engineering, Sustainable Environment, Environmental Chemistry, cleaner production/pollution prevention, Technology for Sustainable Environment, Environmental Engineering, industrial design for environment, metal surface engineering, clean technologies, environmentally benign coating, environmentally conscious manufacturing, green design, waste minimization, waste reduction, environmental sustainability, plasma polymerization, alternative materials, clean manufacturing, metal finishing, engineering, coating processes, innovative technology, industrial innovations, pollution prevention, clean manufacturing designs

Progress and Final Reports:

2002 Progress Report
2003 Progress Report
2004 Progress Report
Final Report