Dear beloved scientist.

I have a question regarding Polyvinilcaprolactam Nanogels (PVCL NGs) synthesis. I used 500 mg VCL, 20 mg BAC, 10mg of SDS and 12.5mg of NaHCO3 were dissolved in 100g of deionized water, heated to 70℃ under nitrogen atmosphere, mechanically stirred for 1h, and then added into KPS aqueous solution (12.5mg, 1mL of deionized water). In nitrogen atmosphere, stir at 70℃ for 6h, and then cool to room temperature in nitrogen atmosphere. But, after 2-3 hours, there is no color change in the reaction solution. I am using anaerobic deionized water (which has been deoxygenated by using N2) as a solvent. Is it normal to have no color change after several hours? How the color of the solution of the success reaction of PVCL NGs? Because it's my first time to do this synthesis. Do you have any opinion that can improve my method? Your opinion regarding this matter is very welcomed.