Paper TF-WeM6
Chemical Vapor Deposition of Sandwiched Antibacterial Layers

Wednesday, October 20, 2010, 9:40 am, Room Ruidoso

To deposit organic polymers on three-dimensional, even rugged surfaces, (pe)cvd is the method of choice. Thickness and film quality are mainly controlled by the number density of the precursors and their mixing ratio which determine the equilibrium of polymerization between reactions in the gas phase at high densities or at the surface for low densities. In most cases, MFCs can be used. Since MFCs can be heated only up to about 80 °C, precursors with low vapor pressure cannot be discharged into the reactor by this method, and the flow is mainly controlled by vapor pressure which limits the controlled deposition of thin layers.

We have recorded the vapor pressure curves for diparylene N and diparylene C applying a dynamic and a static method, resp. [1], and correlated flow and deposition rate with vapor pressure. To meet the demands for exact layer thickness even for values below 1 μm, an almost digital grow method is required. We introduce such a simple, low-cost method for the coat­­ing of antibacterial layers which have been deposited by subsequent wet chemical meth­ods and galvanic plating. For very thin layers, the increase in pinhole density with shrink­­­ing film thickness has been investigated as functions of total pressure and process time by qualitative visual inspection (sem) and quantitative measurements by comparing the permeability of thin films against water vapor and oxygen. For swiss cheese layers, the anti­bacterial film below is but partly protected, however, the anti­bacterial action can be prolonged over years. Eventually, the change in mechanism from polymerization at the surface to volume poly­merization has been investigated by varying the doping levels of the ambient gas (argon or oxygen), and has been correlated in-situ by mass spectrometry and ex-post to some film properties; among them are surface rough­ness and surface energy and the refraction index as well as the ir spectrum which has been modeled for the dimeric and the polymeric species applying a Gaussian method.