| AVS 59th Annual International Symposium and Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS-ThA |
| Session: | Plasma Sources |
| Presenter: | J.D. Whittle, University of South Australia |
| Authors: | J.D. Whittle, University of South Australia A. Michelmore, University of South Australia D.A. Steele, University of South Australia R.D. Short, University of South Australia |
| Correspondent: | Click to Email |
Plasma polymerization is capable of producing adherent pinhole-free thin films with a diverse range of chemical functional groups and physical properties. These materials are used widely in applications ranging from composites, electronics, solar cells and biomaterials. Although a number of plasma processes have been scaled up very successfully and have used sophisticated diagnostics, the majority of researchers utilize lab-built reactor systems with very little in the way of plasma diagnostics, relying on control of external parameters to achieve reproducibility and to guide materials design. Often the focus is on retaining chemical function from the precursor compounds, and these processes are typically described by a limited number of variables, for example, rf power, reactor pressure, monomer flow rate. While these parameters often give reasonable control within a given system, it is not clear to what extent these parameters correlate between systems.This becomes a problem when comparing plasma polymerisation experiments with those in the literature - generally the only practical way to repeat a treatment is to re-engineer the process on ones own system by a trial and error process.
In this paper we report the results of an international round-robin exercise which sought to explore the differences resulting from plasma polymerization using 14 different reactor designs spread across seven countries.
We have explored two separate processes; argon plasma treatment of spin-cast polystyrene films and deposition of plasma polymerized acrylic acid at different discharge powers. In all experiments the monomer or gas flow rate was kept the same, and treatments were carried out at the same nominal power. Surfaces were characterized using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), and the effect of reactor geometry, and other uncontrolled variables on the resulting surface properties was examined.
Whilst we did expect significant differences between these systems, the magnitude of these variations was surprising - for many of the surface properties, the coefficient of variation was in excess of 100%. We speculate on the key factors which influence the observed differences in the resulting surface treatment, and how these differences could be reduced in the future.