Temperature and oxygen for polyacrylamide gel making

 Polyacrylamide gel gets solid quickly when the solution is warm, because the chemical reaction of acrylamide is hastened by higher temperature. If you want to quickly get the gel hard, you had better warm the solution with hot water, or you had better use a hot dryer. In contrast, polyacrylamide gel gets solid slowly when it touches to the oxygen. The part of gel that directly touches to the air gets solid slower than the other area that is surrounded by something. Therefore, gel apparatus is basically designed so that it seals the gel containing space hermetically.