Spin coating a 10-μm-thick layer of negative photoresist (KMPR 1010) at 3000 rpm and at 1000 rpm/s for 30 s and soft baking at 110°C for 5 min prepared a silicon wafer for patterning. Exposure to UV light (420 mJ/cm2) through an iron oxide mask transferred the pattern into the photoresist. The wafer was hard baked at 110°C for 5 min and developed in AZ 917MIF for 3 min. Deep reactive ion etch created trenches in the silicon wafer to a depth of 250 μm (STS Pegasus ICP-DRIE, SPTS Technologies Ltd.). Exposure to oxygen plasma (200 W, 200 mT; March CS-1701) for 15 min stripped the remaining photoresist. A fluorinated silane[(trichloro(1H,1H,2H,2H-perfluorooctyl)silane, Sigma-Aldrich] vapor deposited onto the patterned wafer by placing it in a vacuum desiccator with 20 μl of the silane for 12 hours formed a nonadhesive layer on the exposed silicon surfaces. Rinsing with isopropyl alcohol removed residual silane. Patterned and flat wafers underwent the same silane deposition process.

Dissolving 15 g of poly(styrene-isoprene-styrene) (14% styrene; Sigma-Aldrich) in 100 ml of propyl acetate (Alfa Aesar), with shaking periodically over a 24-hour period to ensure full dissolution, formed a solution for casting against a patterned silicon wafer. Mixing 2 weight % (wt %) titanium dioxide powder (Sigma-Aldrich) with the SIS solution and mixing in a planetary mixer (Thinky ARE-310) for 4 min at 2000 rpm yielded an opaque, white color. A poly(tetrafluoroethylene)-coated metal ring (Norpro 666) placed on the silanized, patterned wafer served to contain the solution at the edges. An 8-g sample of clear SIS solution formed the top, patterned layer. A 6-g sample of white SIS solution formed the bottom layer. Subsequent vacuum desiccation for 12 hours served two purposes: (i) to remove bubbles and (ii) to provide a slow evaporation rate by maintaining a vapor bath around the SIS solution. The samples were dry to the touch after 12 hours. Heating for 6 hours at 80°C on a hot plate removed any remaining solvent. Light pressing and waiting at 30 min was sufficient to form permanent, watertight bonds between the SIS layers and the adhesive.

Note: The content above has been extracted from a research article, so it may not display correctly.



Q&A
Please log in to submit your questions online.
Your question will be posted on the Bio-101 website. We will send your questions to the authors of this protocol and Bio-protocol community members who are experienced with this method. you will be informed using the email address associated with your Bio-protocol account.



We use cookies on this site to enhance your user experience. By using our website, you are agreeing to allow the storage of cookies on your computer.