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2007
Journal Article
Titel
Microplasma-based treatment of inner surfaces in microfluidic devices
Abstract
The paper presents one example of the utilization of microplasmas formed in cavities, which are surrounded partially or completely by dielectric materials, for surface technological processes. The modification or coating of inner surfaces in already sealed polymer- or glass-based microfluidic systems is a challenging new application of atmospheric-pressure microplasmas which promises the achievement of a wide range of physico-chemical surface properties which are difficult to attain by wet-chemical or low-pressure plasma processes. Depending on the type of gas atmosphere or precursor fed into the microfluidic system, hydrophilic or hydrophobic, anionic or cationic, reactive or inert surfaces will be accessible in cost-efficient processes. After an introduction into recent developments in the area of surface functionalization by atmospheric-pressure dielectric barrier discharges and microplasmas, this contribution will describe the coating of inner surfaces of microfluidic devices and the evaluation of film thickness profiles along microfluidic channels using FTIR microspectroscopy. Results of thickness profile measurements are presented and discussed for hydrophilic silicon dioxide coatings as well as hydrophobic deposits obtained from hexamethyl-disiloxane.