The Ohio State University

Surface Modification of Silicon and PDMS Surfaces with Vapor Phase Deposited Ultrathin Fluoropolymer and Fluorosilane Films for Biomedical Micro/Nanoelectromechanical System Applications

By Kang Kug Lee
Masters Dissertation,
Department of Mechanical Engineering, March 2005

ABSTRACT

A vapor phase deposition system was designed for the purpose of coating uniform, conformal and ultrathin coatings of fluoropolymer and fluorosilane thin films inside silicon nanochannels. Surface modifications become increasingly important for biomedical micro/nanoelectromechanical system (BioMEMS/NEMS) applications and vapor phase deposition has advantages over liquid phase deposition since the vapor can permeate more efficiently into silicon nanochannels.Vapor phase deposition was used to deposit various ultrathin films, identifying deposition parameters to optimize the process. The films are desirable to control the hydrophobicity of the surface and reduce or prevent undesired protein adsorption or cell interactions, which may cause detrimental effects to the performance of most BioMEMS/NEMS devices. The films were characterized by means of a contact angle analyzer for hydrophobicity and an ellipsometer for film thickness. Atomic force microscopy was used extensively to collect surface images, adhesive and frictional properties of these films, all of which play a very important role in characterizing uniform, conformal and ultra thin films on the surface.