Supporting Information for Dead-end filling of SlipChip evaluated theoretically and experimentally as a function of the surface chemistry and the gap size between the plates for lubricated and dry SlipChips

Experimental Section: Fabrication of glass devices The procedure for fabrication of SlipChip from glass was based on previous work. 1 The sodalime glass slide with chromium and photoresist coating was aligned with a photomask containing the design for the wells and the ducts, and AZ 1500 positive photoresist was exposed using standard exposure protocols. The glass plate was immersed in 0.1 mol/L NaOH immediately after exposure to remove the areas of the photoresist exposed to UV light. The exposed chromium layer was removed by applying a chromium etchant (a solution of 0.6:0.365 mol/L HClO4 / (NH4)2Ce (NO3)6). The glass plate was then rinsed with Millipore water and dried with nitrogen gas. The back of the glass plate was taped with PVC sealing tape, and then the glass plate was immersed in a glass etching solution (1:0.5:0.75 mol/L HF/NH4F/HNO3) to etch the exposed glass surface where chromium coating was removed in the previous step. The etching speed was controlled by the etching temperature. The glass plate with etched wells was thoroughly rinsed with Millipore water. To make “micropatterns” with ~ 2.5 μm depth, the UV-exposure and etching process described above was repeated with a different mask (10 μm by 10 μm transparent square with 10 mm spacing on 1.5’’ by 3’’ black background) and a shortened etching time (~ 2 minutes), respectively; followed by thorough ethanol rinsing and blow drying with nitrogen gas. The glass plate was oxidized in plasma cleaner for 100 seconds and then immediately transferred into a desiccator. 50 μL of (Tridecafluoro-1,1,2,2 -tetrahydrooctyl) trichlorosilane was injected into the desiccator and vacuum was then applied in the dessicator to perform gas phase silanization for 3 hours. The silanized glass plates were incubated in 120 o oven for 30 minutes and cleaned with a fluorocarbon, FC-3283, and then dried in 65 o oven. Through holes were drilled in the top plate as an inlet for all designs. For devices used for quantification of gap size, dichlorodimethylsilane was used to perform gas phase silanization.