I am following several papers where they have formed hydrogel phantoms which represents artificial lung/brain etc. In almost all the papers, they have performed the same material preparation that is heat the phytagel and PVA separately at 90 Celsius for 1 hour and then mix together on a 1:1 ratio at 70 Celsius for 1 hour. I am wondering regarding the fundamental reason for coming to these and how would it impact had for example I would have heated the mixture at 90 Celsius instead of 70 Celsius for 30 mins.