Experimental Studies on the Effects of Geometric Parameters in a Planar Pneumatic Microvalve

The lateral deflection of a microscale elastomer membrane patterned in polydimethylsiloxane (PDMS) has been experimentally characterized in terms of how geometric parameters affect the compliance of the membrane, and consequently the magnitude of deflection for a given pressure. The concept of a laterally-deformable membrane had been previously demonstrated as viable for applications including sealing, mixing, and sorting. The present work specifically applies fractional factorial experiments to examine the effects of thickness, width, and height of the membrane. It was observed that deflection magnitudes in excess of 10 microns could routinely be achieved with actuation pressure less than 200 kPa. In some cases deflection magnitude as high as 20 microns was also demonstrated. Functional membrane fabrication with dimensions as aggressive as 8 microns thick, 200 microns wide, and 45 microns tall has been successfully demonstrated. Thinner membranes and wider span exhibited similar magnitude of effects in terms of improving compliance. Height of the membrane exhibited a notably larger magnitude of effect, attributed to boundary conditions where the foot of the membrane is bonded to the base substrate. Seal reliability at the foot of the membrane was a significant limitation to sample yield, and represents the primary need for future development.