Nanotribological characterization of vapor phase deposited fluorosilane self-assembled monolayers deposited on polydimethylsiloxane surfaces for biomedical micro-/nanodevices

Abstract

Fluorosilane self-assembled monolayers for polydimethylsiloxane (PDMS) nanochannels are desirable to control the hydrophobicity of the surface to reduce or prevent undesired protein adsorption or cell interactions, critical for the performance of many biomedical micro-/nanodevices. Surface modifications using vapor phase deposition have become increasingly important for some biomedical micro-/nanodevices and have advantages over liquid phase deposition since the vapor phase can permeate more efficiently into nanochannels. In this study, vapor phase deposition was used to deposit four fluorosilanes on PDMS, and deposition conditions for an optimal process were identified. The films were characterized by means of a contact angle analyzer for hydrophobicity and an atomic force microscope for adhesion and friction measurements. The influence of relative humidity, temperature, and sliding velocity on the friction and adhesion behavior is studied. Failure mechanisms of self-assembled monolayers are investigated by wear tests.