{
    "protocol": "The synthesis of hydrophilic polymers with functional groups was achieved using gas-phase processing through Chemical Vapor Deposition (CVD). Specifically, surfaces rich in residual silanol groups were treated by immersion in HMDS (hexamethyldisilazane) in hexane, with concentrations varying from 0% to 100% HMDS for immersion times ranging from 0 to 1400 minutes at room temperature. The goal was to reduce the number of reactive silanol groups on the glass surface to enhance surface wettability. The modifications resulted in an increase in the static contact angle from 25° to 105° after treatment with 100% HMDS for more than 60 minutes.Expose rigid flat samples of glass microscope slides, silicon pieces, SU-8 2005 coatings, and PDMS membranes to HMDS vapor and FDTS vapor at room temperature. After chemical vapor deposition (CVD) exposure, measure the contact angle of liquid drops of deionised water or water-based phosphate-buffered saline solution on the solid surface.Samples of glass and silicon have been washed with Alconox® anionic detergent for 3 hours, rinsed with isopropanol (>99.8%, Labchem) followed by DI water, and blow dried. PDMS membranes have been prepared by manually mixing 3 dimethyl siloxane and 184 silicone elastomer (cross linking agent) in a 10:1 ratio, left for 1 hour on the vacuum desiccator (1-800-4Bel-Art, Bel-Art Products) to remove any bubbles present in the mixture, and cured at 70°C for 1 hour (Memmert GmbH+Co. KG 100–800 oven). SU-8 20055µm thickness homogeneous coating has been defined by a 2-step spin coating on previously dehydrated silicon pieces (step 1: 500 rpm for 10 s at 100 rpm.s^{-1}, step 2: 3056 rpm for 30 s at 300 rpm.s^{-1}; Modular spin coater ws-650-23NPP, Laurell Technologies Inc.). After a soft baking step on a hot plate (95°C for 2 min, SD160 hotplate, Stuart), the SU-8 2005 has been exposed to UV light (17 s, 5.95 W.cm^{-2}, UH-H 254, UV Light Technology LTD; black filter: 320-405 nm), followed by another soft bake step at 95°C for 3 min and finally left to cool to room temperature. All steps have been prepared inside a laminar flow hood (Faster-BSC-EN) to avoid surface contamination.Expose the surface to a volume of 6μL HMDS or FDTS vapor on a vacuum desiccator for 2, 10, 20, 30 or 50 minutes at ambient temperature (22°C) and pressure -0.78 ± 0.09 atm.Contact angle analysis was performed by dispensing 6μL liquid drops of DI water or PBS solution on the surface using a controllable syringe pump (NE 4000, New Era) and a 1mL syringe (CODAN) with polyethylene tubing BTPE-90 863.3μm inner diameter. CA measurements were taken in cleaned, non-exposed control sample surfaces for an exposure time of 0min. Images of each droplet on the surface were captured under ambient conditions within 5min after CVD exposure. The effectiveness and stability of SWM over time were evaluated through CA measurements over 65h after CVD. Droplet images were recorded with a CMOS camera (5.1μm pixel size, 12 Mpixel), coupled with a macro lens with 0.33 maximum magnification. Each combination of experimental conditions (substrate – liquid – CVD fluid – exposure time) was repeated three times. CA evaluation was conducted using Image J software with LBADSA plugin."
}