Adhesion and friction properties of polymers in microfluidic devices

Tribological issues in micro/nanoelectromechanical systems (MEMS/NEMS) and BioMEMS/NEMS are one of the concerns for the reliability of these devices. Silicon based components for MEMS/NEMS devices have been the standard, but new materials, such as polymers, are gaining use due to their advantages over silicon in the area of BioMEMS. Adhesion and friction properties of two polymers of interest, poly(methyl methacrylate) (PMMA) and polydimethylsiloxane (PDMS), along with a single-crystal silicon substrate, Si(100), are investigated by using a novel microtriboapparatus capable of adopting BioMEMS components used in microfluidic devices. The adhesion and friction properties of PMMA and PDMS are dependent upon the surrounding environment, and to study these issues three different liquids are applied to the interface of the contacts in two different forms, a drop and a film. Other environmental effects are also investigated in this study by looking at relative humidity, temperature, rest time and different gaseous environments such as nitrogen gas and reduced pressure.