{
    "protocol": "Prepare sol-gel-derived titania films by dip coating from Ti(OC3H7i)4 solutions containing 2-propanol (2-Pr) as the major solvent and propylene glycol (PG) and dipropylene glycol (DPG) as the co-solvents. Vary the contents of PG and DPG to control the surface tension gradient in the coating layer. The effect of the co-solvents on the spontaneous pattern formation induced by Bénard−Marangoni convection should be systematically discussed.The preparation of hydrophilic polymers with functional groups follows the outlined steps: First, starting solutions with molar compositions of Ti(OC3H7^i)4/H2O/HNO3/2-Pr/PG or DPG were prepared in the ratio 1:2:0.2:40:x or y (where x or y ranges from 0 to 1.50). Begin by adding Ti(OC3H7^i)4 to half of the prescribed amount of 2-Pr. Mix the remaining 2-Pr with H2O and HNO3, and then add this solution dropwise to the Ti(OC3H7^i)4 solution while stirring. Allow the combined solution to stand at room temperature in a sealed glass container for 30 minutes, then add PG or DPG under stirring. Let the solution stand for an additional 3 hours to serve as a coating solution. Titania gel films are then deposited on Si(100) substrates using a dip coater, where substrates are withdrawn at a rate of 50.0 cm/min in a thermostatic oven maintained at 60°C, with solutions and substrates preheated for 30 minutes before dip coating. After gel film deposition, keep at 60°C for 3 minutes, then heat the films at 200 or 600°C for 10 minutes in air."
}