3 lines
4.9 KiB
JSON
3 lines
4.9 KiB
JSON
{
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"protocol": "Ultrathin polymeric membranes can be prepared through interfacial polymerization (IP), typically performed at the gas–liquid interface, where the reactive building blocks are continuously supplied and undergo systematic aggregation.For targeted inorganic production in a mild aqueous reaction, membrane synthesis begins with an arbitrary initial concentration and reaction temperature. After sufficient time, evaluate the GT-phase attributes of the floating solids and adjust the reaction conditions for new synthesis. Repeat the experimental loop to obtain a well-defined membrane, adjusting thickness and through-hole parameters by controlling building unit size and terminal reaction time.The consumable polystyrene Petri dish was used as the reaction vessel for membrane synthesis. The inwall of the Petri dish was manually coated with the PVAAc film of about 1.6x10^{-2} mg mm^{-2}, which can rapidly swell into a hydrogel coat once it makes contact with the aqueous solution. Briefly, the Petri dish was waggled sufficiently following the addition of 500 microliters of PVAAc aqueous solution (3.5 wt%) to guarantee that all of its inwall surface was wetted by the solution. The pretreated Petri dish with PVAAc film coating was then obtained by desiccating it at 70 degrees Celsius for 2 hours, followed by naturally cooling down to room temperature.1. Prepare Tollens’ reagent by mixing 60μl of ammonium hydroxide solution (28-30wt%) with 1.44ml of AgNO3 solution to yield a 120mM solution. 2. Transfer 1.5ml of the fresh Tollens’ reagent solution into a pretreated Petri dish. 3. Add 1.5ml of a mixed solution containing D(+)-glucose (250mM) and NaOH (50mM) to the Petri dish. 4. Allow the mixture to stand at room temperature for 30 minutes to enable the Ag membrane formation on the aqueous solution surface. 5. Transfer the formed Ag membrane onto the surface of deionized water using a glass sheet. 6. Perform a control synthesis in a clean Petri dish with no surface coating under the same conditions.To separate the floating membrane from the reaction Petri dish, first remove the solution using a pipette. Then, add 8 ml deionized water to refloat the membrane. Replace the water inside the dish three times to fully eliminate residual chemicals. Immerse the membrane-held dish in a larger tank full of deionized water to transfer the cleaned membrane to a wider surface. To cut the membrane, lift it using a hydrophobic acrylic plate, cut with a razor blade before the water completely evaporates, and release it to refloat on the water surface for subsequent transfer. For characterization, the membrane can be transferred to various substrates. To prepare a flat membrane for X-ray diffraction (XRD) characterization, create a hydrophilic surface on the hydrophobic acrylic plate by exposing it to 254-nm ultraviolet (UV) light for 15 minutes at room temperature. For membranes that are not water resistant, clean and float them using an acetone solution (about 2-10% in deionized water).Cut a small piece of membrane with dimensions larger than 3 mm and smaller than 4 mm in each direction. Release the membrane to refloat on the surface of deionized water. Suspend the membrane over a copper ring with outer diameter of 4 mm and inner diameter of 2 mm to ensure a single-layer configuration. Use the through-hole membrane for optical observation on an Olympus BX53 microscope after natural drying at room temperature.In a sealed cuboid box (160×100×70 mm³) painted black, place a pretreated dish with 1.5 ml of fresh Tollens' reagent solution (120 mM) at the center. Position a visible fibre-coupled UHP-T-LED light source with a 12 mm diameter collimator 30 mm above the solution surface at a 90° angle from the opposite fibre detector of a spectrometer (Maya2000, Ocean Optics). To start the reaction, introduce 1.5 ml of a mixed D(+)-glucose (250 mM) and NaOH (50 mM) solution from a dropper hanging over the apparatus. Collect in situ reflectance spectra of the air-liquid interface consecutively using Spectra Suite. Collect spectra for five minutes prior to reaction initiation at a rate of 0.2 Hz to estimate measurement stability. For the first 60 seconds after the reaction starts, set acquisition rate at 16.7 Hz; for the remaining 29 minutes, set it at 0.032 Hz.PVAAc aqueous solution (3.5wt%) was applied onto the surface of the bare substrate (area 1x1cm2) at 70°C in an oven and then desiccated for 2h.One millilitre of deionized water was added onto the PVAAc coat on a square glass plate, followed by standing at room temperature for 15 min. The dry PVAAc film swelled into a hydrogel coat, and free water was removed by filter paper to prepare the free-swelling hydrogel coating. A second piece of glass plate was placed on the free-swelling hydrogel coating, and a compressive load of 21.6 N was applied using a Mecmesin MultiTest 1-i tensile and compression test system. Transudatory water was removed by filter paper during 10-min-retained compressive loading."
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